diff --git a/src/battle-scene.ts b/src/battle-scene.ts
index d82acec1c20..9be72366965 100644
--- a/src/battle-scene.ts
+++ b/src/battle-scene.ts
@@ -1261,8 +1261,6 @@ export default class BattleScene extends SceneBase {
       this.currentBattle.mysteryEncounterType = mysteryEncounterType;
     }
 
-    //this.pushPhase(new TrainerMessageTestPhase(this, TrainerType.RIVAL, TrainerType.RIVAL_2, TrainerType.RIVAL_3, TrainerType.RIVAL_4, TrainerType.RIVAL_5, TrainerType.RIVAL_6));
-
     if (!waveIndex && lastBattle) {
       const isWaveIndexMultipleOfTen = !(lastBattle.waveIndex % 10);
       const isEndlessOrDaily = this.gameMode.hasShortBiomes || this.gameMode.isDaily;
diff --git a/src/phases/attempt-capture-phase.ts b/src/phases/attempt-capture-phase.ts
index 483e6eac943..7e7faddb01b 100644
--- a/src/phases/attempt-capture-phase.ts
+++ b/src/phases/attempt-capture-phase.ts
@@ -23,7 +23,7 @@ export class AttemptCapturePhase extends PokemonPhase {
   private pokeball: Phaser.GameObjects.Sprite;
   private originalY: number;
 
-  constructor(scene: BattleScene, targetIndex: integer, pokeballType: PokeballType) {
+  constructor(scene: BattleScene, targetIndex: number, pokeballType: PokeballType) {
     super(scene, BattlerIndex.ENEMY + targetIndex);
 
     this.pokeballType = pokeballType;
@@ -160,7 +160,7 @@ export class AttemptCapturePhase extends PokemonPhase {
     });
   }
 
-  failCatch(shakeCount: integer) {
+  failCatch(shakeCount: number) {
     const pokemon = this.getPokemon();
 
     this.scene.playSound("se/pb_rel");
@@ -262,7 +262,7 @@ export class AttemptCapturePhase extends PokemonPhase {
                   });
                 }, false);
               }, () => {
-                this.scene.ui.setMode(Mode.PARTY, PartyUiMode.RELEASE, this.fieldIndex, (slotIndex: integer, _option: PartyOption) => {
+                this.scene.ui.setMode(Mode.PARTY, PartyUiMode.RELEASE, this.fieldIndex, (slotIndex: number, _option: PartyOption) => {
                   this.scene.ui.setMode(Mode.MESSAGE).then(() => {
                     if (slotIndex < 6) {
                       addToParty(slotIndex);
diff --git a/src/phases/battle-phase.ts b/src/phases/battle-phase.ts
index 11807fdc714..708e0d2afed 100644
--- a/src/phases/battle-phase.ts
+++ b/src/phases/battle-phase.ts
@@ -8,8 +8,12 @@ export class BattlePhase extends Phase {
   }
 
   showEnemyTrainer(trainerSlot: TrainerSlot = TrainerSlot.NONE): void {
-    const sprites = this.scene.currentBattle.trainer?.getSprites()!; // TODO: is this bang correct?
-    const tintSprites = this.scene.currentBattle.trainer?.getTintSprites()!; // TODO: is this bang correct?
+    if (!this.scene.currentBattle.trainer) {
+      console.warn("Enemy trainer is missing!");
+      return;
+    }
+    const sprites = this.scene.currentBattle.trainer.getSprites();
+    const tintSprites = this.scene.currentBattle.trainer.getTintSprites();
     for (let i = 0; i < sprites.length; i++) {
       const visible = !trainerSlot || !i === (trainerSlot === TrainerSlot.TRAINER) || sprites.length < 2;
       [ sprites[i], tintSprites[i] ].map(sprite => {
diff --git a/src/phases/check-status-effect-phase.ts b/src/phases/check-status-effect-phase.ts
index 44918b54966..8b6d4bf08c4 100644
--- a/src/phases/check-status-effect-phase.ts
+++ b/src/phases/check-status-effect-phase.ts
@@ -4,10 +4,9 @@ import { BattlerIndex } from "#app/battle";
 import BattleScene from "#app/battle-scene";
 
 export class CheckStatusEffectPhase extends Phase {
-  private order : BattlerIndex[];
-  constructor(scene : BattleScene, order : BattlerIndex[]) {
+  private order: BattlerIndex[];
+  constructor(scene: BattleScene, order: BattlerIndex[]) {
     super(scene);
-    this.scene = scene;
     this.order = order;
   }
 
diff --git a/src/phases/check-switch-phase.ts b/src/phases/check-switch-phase.ts
index b87dff32f60..9ae720fbe8e 100644
--- a/src/phases/check-switch-phase.ts
+++ b/src/phases/check-switch-phase.ts
@@ -11,10 +11,10 @@ import { SwitchPhase } from "./switch-phase";
 import { SwitchType } from "#enums/switch-type";
 
 export class CheckSwitchPhase extends BattlePhase {
-  protected fieldIndex: integer;
+  protected fieldIndex: number;
   protected useName: boolean;
 
-  constructor(scene: BattleScene, fieldIndex: integer, useName: boolean) {
+  constructor(scene: BattleScene, fieldIndex: number, useName: boolean) {
     super(scene);
 
     this.fieldIndex = fieldIndex;
diff --git a/src/phases/command-phase.ts b/src/phases/command-phase.ts
index c1d38815c2f..0b0ab102948 100644
--- a/src/phases/command-phase.ts
+++ b/src/phases/command-phase.ts
@@ -21,9 +21,9 @@ import { ArenaTagSide } from "#app/data/arena-tag";
 import { ArenaTagType } from "#app/enums/arena-tag-type";
 
 export class CommandPhase extends FieldPhase {
-  protected fieldIndex: integer;
+  protected fieldIndex: number;
 
-  constructor(scene: BattleScene, fieldIndex: integer) {
+  constructor(scene: BattleScene, fieldIndex: number) {
     super(scene);
 
     this.fieldIndex = fieldIndex;
@@ -90,7 +90,7 @@ export class CommandPhase extends FieldPhase {
     }
   }
 
-  handleCommand(command: Command, cursor: integer, ...args: any[]): boolean {
+  handleCommand(command: Command, cursor: number, ...args: any[]): boolean {
     const playerPokemon = this.scene.getPlayerField()[this.fieldIndex];
     let success: boolean;
 
@@ -307,7 +307,7 @@ export class CommandPhase extends FieldPhase {
     return true;
   }
 
-  getFieldIndex(): integer {
+  getFieldIndex(): number {
     return this.fieldIndex;
   }
 
diff --git a/src/phases/common-anim-phase.ts b/src/phases/common-anim-phase.ts
index c4071488eef..8a4f903c371 100644
--- a/src/phases/common-anim-phase.ts
+++ b/src/phases/common-anim-phase.ts
@@ -5,13 +5,13 @@ import { PokemonPhase } from "./pokemon-phase";
 
 export class CommonAnimPhase extends PokemonPhase {
   private anim: CommonAnim | null;
-  private targetIndex: integer | undefined;
+  private targetIndex?: BattlerIndex;
   private playOnEmptyField: boolean;
 
-  constructor(scene: BattleScene, battlerIndex?: BattlerIndex, targetIndex?: BattlerIndex | undefined, anim?: CommonAnim, playOnEmptyField: boolean = false) {
+  constructor(scene: BattleScene, battlerIndex?: BattlerIndex, targetIndex?: BattlerIndex, anim: CommonAnim | null = null, playOnEmptyField: boolean = false) {
     super(scene, battlerIndex);
 
-    this.anim = anim!; // TODO: is this bang correct?
+    this.anim = anim;
     this.targetIndex = targetIndex;
     this.playOnEmptyField = playOnEmptyField;
   }
diff --git a/src/phases/damage-phase.ts b/src/phases/damage-phase.ts
index 44e3dfd4182..ba3947bd595 100644
--- a/src/phases/damage-phase.ts
+++ b/src/phases/damage-phase.ts
@@ -6,15 +6,15 @@ import * as Utils from "#app/utils";
 import { PokemonPhase } from "./pokemon-phase";
 
 export class DamagePhase extends PokemonPhase {
-  private amount: integer;
+  private amount: number;
   private damageResult: DamageResult;
   private critical: boolean;
 
-  constructor(scene: BattleScene, battlerIndex: BattlerIndex, amount: integer, damageResult?: DamageResult, critical: boolean = false) {
+  constructor(scene: BattleScene, battlerIndex: BattlerIndex, amount: number, damageResult: DamageResult = HitResult.EFFECTIVE, critical: boolean = false) {
     super(scene, battlerIndex);
 
     this.amount = amount;
-    this.damageResult = damageResult || HitResult.EFFECTIVE;
+    this.damageResult = damageResult;
     this.critical = critical;
   }
 
@@ -35,7 +35,7 @@ export class DamagePhase extends PokemonPhase {
     this.applyDamage();
   }
 
-  updateAmount(amount: integer): void {
+  updateAmount(amount: number): void {
     this.amount = amount;
   }
 
diff --git a/src/phases/egg-hatch-phase.ts b/src/phases/egg-hatch-phase.ts
index 90aceeb46bc..00954ea895f 100644
--- a/src/phases/egg-hatch-phase.ts
+++ b/src/phases/egg-hatch-phase.ts
@@ -26,7 +26,7 @@ export class EggHatchPhase extends Phase {
   private eggHatchData: EggHatchData;
 
   /** The number of eggs that are hatching */
-  private eggsToHatchCount: integer;
+  private eggsToHatchCount: number;
   /** The container that lists how many eggs are hatching */
   private eggCounterContainer: EggCounterContainer;
 
@@ -57,7 +57,7 @@ export class EggHatchPhase extends Phase {
   /** The newly hatched {@link PlayerPokemon} */
   private pokemon: PlayerPokemon;
   /** The index of which egg move is unlocked. 0-2 is common, 3 is rare */
-  private eggMoveIndex: integer;
+  private eggMoveIndex: number;
   /** Internal booleans representing if the egg is hatched, able to be skipped, or skipped */
   private hatched: boolean;
   private canSkip: boolean;
@@ -66,7 +66,7 @@ export class EggHatchPhase extends Phase {
   private evolutionBgm: AnySound;
   private eggLapsePhase: EggLapsePhase;
 
-  constructor(scene: BattleScene, hatchScene: EggLapsePhase, egg: Egg, eggsToHatchCount: integer) {
+  constructor(scene: BattleScene, hatchScene: EggLapsePhase, egg: Egg, eggsToHatchCount: number) {
     super(scene);
     this.eggLapsePhase = hatchScene;
     this.egg = egg;
@@ -219,7 +219,7 @@ export class EggHatchPhase extends Phase {
    * @param count the current number of times this function has been called.
    * @returns nothing since it's a Promise<void>
    */
-  doEggShake(intensity: number, repeatCount?: integer, count?: integer): Promise<void> {
+  doEggShake(intensity: number, repeatCount?: number, count?: number): Promise<void> {
     return new Promise(resolve => {
       if (repeatCount === undefined) {
         repeatCount = 0;
@@ -376,7 +376,7 @@ export class EggHatchPhase extends Phase {
    * @param amplitude Scaling
    * @returns a number
    */
-  sin(index: integer, amplitude: integer): number {
+  sin(index: number, amplitude: number): number {
     return amplitude * Math.sin(index * (Math.PI / 128));
   }
 
@@ -385,7 +385,7 @@ export class EggHatchPhase extends Phase {
    * @param intensity number of times this is repeated (this is a badly named variable)
    * @param offsetY how much to offset the Y coordinates
    */
-  doSpray(intensity: integer, offsetY?: number) {
+  doSpray(intensity: number, offsetY?: number) {
     this.scene.tweens.addCounter({
       repeat: intensity,
       duration: Utils.getFrameMs(1),
@@ -400,7 +400,7 @@ export class EggHatchPhase extends Phase {
    * @param trigIndex Used to modify the particle's vertical speed, is a random number from 0-7
    * @param offsetY how much to offset the Y coordinate
    */
-  doSprayParticle(trigIndex: integer, offsetY: number) {
+  doSprayParticle(trigIndex: number, offsetY: number) {
     const initialX = this.eggHatchBg.displayWidth / 2;
     const initialY = this.eggHatchBg.displayHeight / 2 + offsetY;
     const shardKey = !this.egg.isManaphyEgg() ? this.egg.tier.toString() : "1";
diff --git a/src/phases/encounter-phase.ts b/src/phases/encounter-phase.ts
index c4d919c0325..e0ac06d48a0 100644
--- a/src/phases/encounter-phase.ts
+++ b/src/phases/encounter-phase.ts
@@ -40,10 +40,10 @@ import { WEIGHT_INCREMENT_ON_SPAWN_MISS } from "#app/data/mystery-encounters/mys
 export class EncounterPhase extends BattlePhase {
   private loaded: boolean;
 
-  constructor(scene: BattleScene, loaded?: boolean) {
+  constructor(scene: BattleScene, loaded: boolean = false) {
     super(scene);
 
-    this.loaded = !!loaded;
+    this.loaded = loaded;
   }
 
   start() {
@@ -268,7 +268,7 @@ export class EncounterPhase extends BattlePhase {
     const enemyField = this.scene.getEnemyField();
     this.scene.tweens.add({
       targets: [ this.scene.arenaEnemy, this.scene.currentBattle.trainer, enemyField, this.scene.arenaPlayer, this.scene.trainer ].flat(),
-      x: (_target, _key, value, fieldIndex: integer) => fieldIndex < 2 + (enemyField.length) ? value + 300 : value - 300,
+      x: (_target, _key, value, fieldIndex: number) => fieldIndex < 2 + (enemyField.length) ? value + 300 : value - 300,
       duration: 2000,
       onComplete: () => {
         if (!this.tryOverrideForBattleSpec()) {
diff --git a/src/phases/enemy-command-phase.ts b/src/phases/enemy-command-phase.ts
index 3647a237ef1..418debdc782 100644
--- a/src/phases/enemy-command-phase.ts
+++ b/src/phases/enemy-command-phase.ts
@@ -13,10 +13,10 @@ import { FieldPhase } from "./field-phase";
  * @see {@linkcode EnemyPokemon.getNextMove}
  */
 export class EnemyCommandPhase extends FieldPhase {
-  protected fieldIndex: integer;
+  protected fieldIndex: number;
   protected skipTurn: boolean = false;
 
-  constructor(scene: BattleScene, fieldIndex: integer) {
+  constructor(scene: BattleScene, fieldIndex: number) {
     super(scene);
 
     this.fieldIndex = fieldIndex;
diff --git a/src/phases/enemy-party-member-pokemon-phase.ts b/src/phases/enemy-party-member-pokemon-phase.ts
index bb34f53b475..97c3dccd0c2 100644
--- a/src/phases/enemy-party-member-pokemon-phase.ts
+++ b/src/phases/enemy-party-member-pokemon-phase.ts
@@ -3,7 +3,7 @@ import { EnemyPokemon } from "#app/field/pokemon";
 import { PartyMemberPokemonPhase } from "./party-member-pokemon-phase";
 
 export abstract class EnemyPartyMemberPokemonPhase extends PartyMemberPokemonPhase {
-  constructor(scene: BattleScene, partyMemberIndex: integer) {
+  constructor(scene: BattleScene, partyMemberIndex: number) {
     super(scene, partyMemberIndex, false);
   }
 
diff --git a/src/phases/evolution-phase.ts b/src/phases/evolution-phase.ts
index dec65e2c945..3bf4022b2a8 100644
--- a/src/phases/evolution-phase.ts
+++ b/src/phases/evolution-phase.ts
@@ -15,7 +15,7 @@ import { EndEvolutionPhase } from "#app/phases/end-evolution-phase";
 
 export class EvolutionPhase extends Phase {
   protected pokemon: PlayerPokemon;
-  protected lastLevel: integer;
+  protected lastLevel: number;
 
   private preEvolvedPokemonName: string;
 
@@ -33,7 +33,7 @@ export class EvolutionPhase extends Phase {
   protected pokemonEvoSprite: Phaser.GameObjects.Sprite;
   protected pokemonEvoTintSprite: Phaser.GameObjects.Sprite;
 
-  constructor(scene: BattleScene, pokemon: PlayerPokemon, evolution: SpeciesFormEvolution | null, lastLevel: integer) {
+  constructor(scene: BattleScene, pokemon: PlayerPokemon, evolution: SpeciesFormEvolution | null, lastLevel: number) {
     super(scene);
 
     this.pokemon = pokemon;
@@ -339,7 +339,7 @@ export class EvolutionPhase extends Phase {
     });
   }
 
-  doCycle(l: number, lastCycle: integer = 15): Promise<boolean> {
+  doCycle(l: number, lastCycle: number = 15): Promise<boolean> {
     return new Promise(resolve => {
       const isLastCycle = l === lastCycle;
       this.scene.tweens.add({
@@ -410,7 +410,7 @@ export class EvolutionPhase extends Phase {
     });
   }
 
-  doSpiralUpwardParticle(trigIndex: integer) {
+  doSpiralUpwardParticle(trigIndex: number) {
     const initialX = this.evolutionBaseBg.displayWidth / 2;
     const particle = this.scene.add.image(initialX, 0, "evo_sparkle");
     this.evolutionContainer.add(particle);
@@ -446,7 +446,7 @@ export class EvolutionPhase extends Phase {
     updateParticle();
   }
 
-  doArcDownParticle(trigIndex: integer) {
+  doArcDownParticle(trigIndex: number) {
     const initialX = this.evolutionBaseBg.displayWidth / 2;
     const particle = this.scene.add.image(initialX, 0, "evo_sparkle");
     particle.setScale(0.5);
@@ -479,7 +479,7 @@ export class EvolutionPhase extends Phase {
     updateParticle();
   }
 
-  doCircleInwardParticle(trigIndex: integer, speed: integer) {
+  doCircleInwardParticle(trigIndex: number, speed: number) {
     const initialX = this.evolutionBaseBg.displayWidth / 2;
     const initialY = this.evolutionBaseBg.displayHeight / 2;
     const particle = this.scene.add.image(initialX, initialY, "evo_sparkle");
@@ -511,7 +511,7 @@ export class EvolutionPhase extends Phase {
     updateParticle();
   }
 
-  doSprayParticle(trigIndex: integer) {
+  doSprayParticle(trigIndex: number) {
     const initialX = this.evolutionBaseBg.displayWidth / 2;
     const initialY = this.evolutionBaseBg.displayHeight / 2;
     const particle = this.scene.add.image(initialX, initialY, "evo_sparkle");
diff --git a/src/phases/exp-phase.ts b/src/phases/exp-phase.ts
index 81982980d2a..9c445f28298 100644
--- a/src/phases/exp-phase.ts
+++ b/src/phases/exp-phase.ts
@@ -9,7 +9,7 @@ import { LevelUpPhase } from "./level-up-phase";
 export class ExpPhase extends PlayerPartyMemberPokemonPhase {
   private expValue: number;
 
-  constructor(scene: BattleScene, partyMemberIndex: integer, expValue: number) {
+  constructor(scene: BattleScene, partyMemberIndex: number, expValue: number) {
     super(scene, partyMemberIndex);
 
     this.expValue = expValue;
diff --git a/src/phases/game-over-phase.ts b/src/phases/game-over-phase.ts
index 84fad257897..78fca492aae 100644
--- a/src/phases/game-over-phase.ts
+++ b/src/phases/game-over-phase.ts
@@ -29,10 +29,10 @@ export class GameOverPhase extends BattlePhase {
   private victory: boolean;
   private firstRibbons: PokemonSpecies[] = [];
 
-  constructor(scene: BattleScene, victory?: boolean) {
+  constructor(scene: BattleScene, victory: boolean = false) {
     super(scene);
 
-    this.victory = !!victory;
+    this.victory = victory;
   }
 
   start() {
diff --git a/src/phases/learn-move-phase.ts b/src/phases/learn-move-phase.ts
index fefda384092..e05b82c63f2 100644
--- a/src/phases/learn-move-phase.ts
+++ b/src/phases/learn-move-phase.ts
@@ -25,10 +25,10 @@ export enum LearnMoveType {
 export class LearnMovePhase extends PlayerPartyMemberPokemonPhase {
   private moveId: Moves;
   private messageMode: Mode;
-  private learnMoveType;
+  private learnMoveType: LearnMoveType;
   private cost: number;
 
-  constructor(scene: BattleScene, partyMemberIndex: integer, moveId: Moves, learnMoveType: LearnMoveType = LearnMoveType.LEARN_MOVE, cost: number = -1) {
+  constructor(scene: BattleScene, partyMemberIndex: number, moveId: Moves, learnMoveType: LearnMoveType = LearnMoveType.LEARN_MOVE, cost: number = -1) {
     super(scene, partyMemberIndex);
     this.moveId = moveId;
     this.learnMoveType = learnMoveType;
@@ -98,7 +98,7 @@ export class LearnMovePhase extends PlayerPartyMemberPokemonPhase {
   async forgetMoveProcess(move: Move, pokemon: Pokemon) {
     this.scene.ui.setMode(this.messageMode);
     await this.scene.ui.showTextPromise(i18next.t("battle:learnMoveForgetQuestion"), undefined, true);
-    await this.scene.ui.setModeWithoutClear(Mode.SUMMARY, pokemon, SummaryUiMode.LEARN_MOVE, move, (moveIndex: integer) => {
+    await this.scene.ui.setModeWithoutClear(Mode.SUMMARY, pokemon, SummaryUiMode.LEARN_MOVE, move, (moveIndex: number) => {
       if (moveIndex === 4) {
         this.scene.ui.setMode(this.messageMode).then(() => this.rejectMoveAndEnd(move, pokemon));
         return;
diff --git a/src/phases/level-up-phase.ts b/src/phases/level-up-phase.ts
index a2fa8a16533..c48c92720ea 100644
--- a/src/phases/level-up-phase.ts
+++ b/src/phases/level-up-phase.ts
@@ -10,10 +10,10 @@ import { PlayerPartyMemberPokemonPhase } from "./player-party-member-pokemon-pha
 import { LearnMovePhase } from "./learn-move-phase";
 
 export class LevelUpPhase extends PlayerPartyMemberPokemonPhase {
-  private lastLevel: integer;
-  private level: integer;
+  private lastLevel: number;
+  private level: number;
 
-  constructor(scene: BattleScene, partyMemberIndex: integer, lastLevel: integer, level: integer) {
+  constructor(scene: BattleScene, partyMemberIndex: number, lastLevel: number, level: number) {
     super(scene, partyMemberIndex);
 
     this.lastLevel = lastLevel;
diff --git a/src/phases/login-phase.ts b/src/phases/login-phase.ts
index ac1e68d1b0e..d181fb08613 100644
--- a/src/phases/login-phase.ts
+++ b/src/phases/login-phase.ts
@@ -11,10 +11,10 @@ import { UnavailablePhase } from "./unavailable-phase";
 export class LoginPhase extends Phase {
   private showText: boolean;
 
-  constructor(scene: BattleScene, showText?: boolean) {
+  constructor(scene: BattleScene, showText: boolean = true) {
     super(scene);
 
-    this.showText = showText === undefined || !!showText;
+    this.showText = showText;
   }
 
   start(): void {
diff --git a/src/phases/message-phase.ts b/src/phases/message-phase.ts
index 1d953801178..bb76edcfe08 100644
--- a/src/phases/message-phase.ts
+++ b/src/phases/message-phase.ts
@@ -3,18 +3,18 @@ import { Phase } from "#app/phase";
 
 export class MessagePhase extends Phase {
   private text: string;
-  private callbackDelay: integer | null;
-  private prompt: boolean | null;
-  private promptDelay: integer | null;
+  private callbackDelay?: number | null;
+  private prompt?: boolean | null;
+  private promptDelay?: number | null;
   private speaker?: string;
 
-  constructor(scene: BattleScene, text: string, callbackDelay?: integer | null, prompt?: boolean | null, promptDelay?: integer | null, speaker?: string) {
+  constructor(scene: BattleScene, text: string, callbackDelay?: number | null, prompt?: boolean | null, promptDelay?: number | null, speaker?: string) {
     super(scene);
 
     this.text = text;
-    this.callbackDelay = callbackDelay!; // TODO: is this bang correct?
-    this.prompt = prompt!; // TODO: is this bang correct?
-    this.promptDelay = promptDelay!; // TODO: is this bang correct?
+    this.callbackDelay = callbackDelay;
+    this.prompt = prompt;
+    this.promptDelay = promptDelay;
     this.speaker = speaker;
   }
 
diff --git a/src/phases/money-reward-phase.ts b/src/phases/money-reward-phase.ts
index 2f0a4f7b990..3b7ea6787d9 100644
--- a/src/phases/money-reward-phase.ts
+++ b/src/phases/money-reward-phase.ts
@@ -15,7 +15,7 @@ export class MoneyRewardPhase extends BattlePhase {
   }
 
   start() {
-    const moneyAmount = new Utils.IntegerHolder(this.scene.getWaveMoneyAmount(this.moneyMultiplier));
+    const moneyAmount = new Utils.NumberHolder(this.scene.getWaveMoneyAmount(this.moneyMultiplier));
 
     this.scene.applyModifiers(MoneyMultiplierModifier, true, moneyAmount);
 
diff --git a/src/phases/move-anim-test-phase.ts b/src/phases/move-anim-test-phase.ts
deleted file mode 100644
index e4b04ce5de6..00000000000
--- a/src/phases/move-anim-test-phase.ts
+++ /dev/null
@@ -1,46 +0,0 @@
-import BattleScene from "#app/battle-scene";
-import { initMoveAnim, loadMoveAnimAssets, MoveAnim } from "#app/data/battle-anims";
-import { allMoves, SelfStatusMove } from "#app/data/move";
-import { Moves } from "#app/enums/moves";
-import * as Utils from "#app/utils";
-import { BattlePhase } from "./battle-phase";
-
-export class MoveAnimTestPhase extends BattlePhase {
-  private moveQueue: Moves[];
-
-  constructor(scene: BattleScene, moveQueue?: Moves[]) {
-    super(scene);
-
-    this.moveQueue = moveQueue || Utils.getEnumValues(Moves).slice(1);
-  }
-
-  start() {
-    const moveQueue = this.moveQueue.slice(0);
-    this.playMoveAnim(moveQueue, true);
-  }
-
-  playMoveAnim(moveQueue: Moves[], player: boolean) {
-    const moveId = player ? moveQueue[0] : moveQueue.shift();
-    if (moveId === undefined) {
-      this.playMoveAnim(this.moveQueue.slice(0), true);
-      return;
-    } else if (player) {
-      console.log(Moves[moveId]);
-    }
-
-    initMoveAnim(this.scene, moveId).then(() => {
-      loadMoveAnimAssets(this.scene, [ moveId ], true)
-        .then(() => {
-          const user = player ? this.scene.getPlayerPokemon()! : this.scene.getEnemyPokemon()!;
-          const target = (player !== (allMoves[moveId] instanceof SelfStatusMove)) ? this.scene.getEnemyPokemon()! : this.scene.getPlayerPokemon()!;
-          new MoveAnim(moveId, user, target.getBattlerIndex()).play(this.scene, allMoves[moveId].hitsSubstitute(user, target), () => { // TODO: are the bangs correct here?
-            if (player) {
-              this.playMoveAnim(moveQueue, false);
-            } else {
-              this.playMoveAnim(moveQueue, true);
-            }
-          });
-        });
-    });
-  }
-}
diff --git a/src/phases/party-member-pokemon-phase.ts b/src/phases/party-member-pokemon-phase.ts
index f2e2b23bfb2..174a428cd46 100644
--- a/src/phases/party-member-pokemon-phase.ts
+++ b/src/phases/party-member-pokemon-phase.ts
@@ -3,11 +3,11 @@ import Pokemon from "#app/field/pokemon";
 import { FieldPhase } from "./field-phase";
 
 export abstract class PartyMemberPokemonPhase extends FieldPhase {
-  protected partyMemberIndex: integer;
-  protected fieldIndex: integer;
+  protected partyMemberIndex: number;
+  protected fieldIndex: number;
   protected player: boolean;
 
-  constructor(scene: BattleScene, partyMemberIndex: integer, player: boolean) {
+  constructor(scene: BattleScene, partyMemberIndex: number, player: boolean) {
     super(scene);
 
     this.partyMemberIndex = partyMemberIndex;
diff --git a/src/phases/player-party-member-pokemon-phase.ts b/src/phases/player-party-member-pokemon-phase.ts
index 87855b9334c..caa5f25c0b8 100644
--- a/src/phases/player-party-member-pokemon-phase.ts
+++ b/src/phases/player-party-member-pokemon-phase.ts
@@ -3,7 +3,7 @@ import { PlayerPokemon } from "#app/field/pokemon";
 import { PartyMemberPokemonPhase } from "./party-member-pokemon-phase";
 
 export abstract class PlayerPartyMemberPokemonPhase extends PartyMemberPokemonPhase {
-  constructor(scene: BattleScene, partyMemberIndex: integer) {
+  constructor(scene: BattleScene, partyMemberIndex: number) {
     super(scene, partyMemberIndex, true);
   }
 
diff --git a/src/phases/pokemon-anim-phase.ts b/src/phases/pokemon-anim-phase.ts
index 26ae11d1026..3bced389438 100644
--- a/src/phases/pokemon-anim-phase.ts
+++ b/src/phases/pokemon-anim-phase.ts
@@ -7,18 +7,18 @@ import { BattlePhase } from "#app/phases/battle-phase";
 
 export class PokemonAnimPhase extends BattlePhase {
   /** The type of animation to play in this phase */
-  private key: PokemonAnimType;
+  protected key: PokemonAnimType;
   /** The Pokemon to which this animation applies */
-  private pokemon: Pokemon;
+  protected pokemon: Pokemon;
   /** Any other field sprites affected by this animation */
-  private fieldAssets: Phaser.GameObjects.Sprite[];
+  protected fieldAssets: Phaser.GameObjects.Sprite[];
 
-  constructor(scene: BattleScene, key: PokemonAnimType, pokemon: Pokemon, fieldAssets?: Phaser.GameObjects.Sprite[]) {
+  constructor(scene: BattleScene, key: PokemonAnimType, pokemon: Pokemon, fieldAssets: Phaser.GameObjects.Sprite[] = []) {
     super(scene);
 
     this.key = key;
     this.pokemon = pokemon;
-    this.fieldAssets = fieldAssets ?? [];
+    this.fieldAssets = fieldAssets;
   }
 
   start(): void {
diff --git a/src/phases/pokemon-heal-phase.ts b/src/phases/pokemon-heal-phase.ts
index dc0bd235bb5..1cafdf18c10 100644
--- a/src/phases/pokemon-heal-phase.ts
+++ b/src/phases/pokemon-heal-phase.ts
@@ -14,7 +14,7 @@ import { BattlerTagType } from "#app/enums/battler-tag-type";
 import { HealBlockTag } from "#app/data/battler-tags";
 
 export class PokemonHealPhase extends CommonAnimPhase {
-  private hpHealed: integer;
+  private hpHealed: number;
   private message: string | null;
   private showFullHpMessage: boolean;
   private skipAnim: boolean;
@@ -22,7 +22,7 @@ export class PokemonHealPhase extends CommonAnimPhase {
   private healStatus: boolean;
   private preventFullHeal: boolean;
 
-  constructor(scene: BattleScene, battlerIndex: BattlerIndex, hpHealed: integer, message: string | null, showFullHpMessage: boolean, skipAnim: boolean = false, revive: boolean = false, healStatus: boolean = false, preventFullHeal: boolean = false) {
+  constructor(scene: BattleScene, battlerIndex: BattlerIndex, hpHealed: number, message: string | null, showFullHpMessage: boolean, skipAnim: boolean = false, revive: boolean = false, healStatus: boolean = false, preventFullHeal: boolean = false) {
     super(scene, battlerIndex, undefined, CommonAnim.HEALTH_UP);
 
     this.hpHealed = hpHealed;
@@ -59,7 +59,7 @@ export class PokemonHealPhase extends CommonAnimPhase {
       this.message = null;
       return super.end();
     } else if (healOrDamage) {
-      const hpRestoreMultiplier = new Utils.IntegerHolder(1);
+      const hpRestoreMultiplier = new Utils.NumberHolder(1);
       if (!this.revive) {
         this.scene.applyModifiers(HealingBoosterModifier, this.player, hpRestoreMultiplier);
       }
diff --git a/src/phases/pokemon-phase.ts b/src/phases/pokemon-phase.ts
index b980c1d1719..b0019a65a5a 100644
--- a/src/phases/pokemon-phase.ts
+++ b/src/phases/pokemon-phase.ts
@@ -4,15 +4,16 @@ import Pokemon from "#app/field/pokemon";
 import { FieldPhase } from "./field-phase";
 
 export abstract class PokemonPhase extends FieldPhase {
-  protected battlerIndex: BattlerIndex | integer;
+  protected battlerIndex: BattlerIndex | number;
   public player: boolean;
-  public fieldIndex: integer;
+  public fieldIndex: number;
 
-  constructor(scene: BattleScene, battlerIndex?: BattlerIndex | integer) {
+  constructor(scene: BattleScene, battlerIndex?: BattlerIndex | number) {
     super(scene);
 
+    battlerIndex = battlerIndex ?? scene.getField().find(p => p?.isActive())!.getBattlerIndex(); // TODO: is the bang correct here?
     if (battlerIndex === undefined) {
-      battlerIndex = scene.getField().find(p => p?.isActive())!.getBattlerIndex(); // TODO: is the bang correct here?
+      console.warn("There are no Pokemon on the field!"); // TODO: figure out a suitable fallback behavior
     }
 
     this.battlerIndex = battlerIndex;
diff --git a/src/phases/post-game-over-phase.ts b/src/phases/post-game-over-phase.ts
index beeb30c7260..2fbd53e5c50 100644
--- a/src/phases/post-game-over-phase.ts
+++ b/src/phases/post-game-over-phase.ts
@@ -4,12 +4,12 @@ import { EndCardPhase } from "./end-card-phase";
 import { TitlePhase } from "./title-phase";
 
 export class PostGameOverPhase extends Phase {
-  private endCardPhase: EndCardPhase | null;
+  private endCardPhase?: EndCardPhase;
 
   constructor(scene: BattleScene, endCardPhase?: EndCardPhase) {
     super(scene);
 
-    this.endCardPhase = endCardPhase!; // TODO: is this bang correct?
+    this.endCardPhase = endCardPhase;
   }
 
   start() {
diff --git a/src/phases/reload-session-phase.ts b/src/phases/reload-session-phase.ts
index f8a38105869..16cefe02c14 100644
--- a/src/phases/reload-session-phase.ts
+++ b/src/phases/reload-session-phase.ts
@@ -4,12 +4,12 @@ import { Mode } from "#app/ui/ui";
 import * as Utils from "#app/utils";
 
 export class ReloadSessionPhase extends Phase {
-  private systemDataStr: string | null;
+  private systemDataStr?: string;
 
   constructor(scene: BattleScene, systemDataStr?: string) {
     super(scene);
 
-    this.systemDataStr = systemDataStr ?? null;
+    this.systemDataStr = systemDataStr;
   }
 
   start(): void {
diff --git a/src/phases/return-phase.ts b/src/phases/return-phase.ts
index eb587201585..250f748db89 100644
--- a/src/phases/return-phase.ts
+++ b/src/phases/return-phase.ts
@@ -4,7 +4,7 @@ import { SwitchType } from "#enums/switch-type";
 import { SwitchSummonPhase } from "./switch-summon-phase";
 
 export class ReturnPhase extends SwitchSummonPhase {
-  constructor(scene: BattleScene, fieldIndex: integer) {
+  constructor(scene: BattleScene, fieldIndex: number) {
     super(scene, SwitchType.SWITCH, fieldIndex, -1, true);
   }
 
diff --git a/src/phases/scan-ivs-phase.ts b/src/phases/scan-ivs-phase.ts
index 5ec61d5eec6..71ef41000f4 100644
--- a/src/phases/scan-ivs-phase.ts
+++ b/src/phases/scan-ivs-phase.ts
@@ -9,9 +9,9 @@ import i18next from "i18next";
 import { PokemonPhase } from "./pokemon-phase";
 
 export class ScanIvsPhase extends PokemonPhase {
-  private shownIvs: integer;
+  private shownIvs: number;
 
-  constructor(scene: BattleScene, battlerIndex: BattlerIndex, shownIvs: integer) {
+  constructor(scene: BattleScene, battlerIndex: BattlerIndex, shownIvs: number) {
     super(scene, battlerIndex);
 
     this.shownIvs = shownIvs;
diff --git a/src/phases/select-biome-phase.ts b/src/phases/select-biome-phase.ts
index 817cd7bcd3d..e03d0b4c025 100644
--- a/src/phases/select-biome-phase.ts
+++ b/src/phases/select-biome-phase.ts
@@ -37,7 +37,7 @@ export class SelectBiomePhase extends BattlePhase {
     } else if (Array.isArray(biomeLinks[currentBiome])) {
       let biomes: Biome[] = [];
       this.scene.executeWithSeedOffset(() => {
-        biomes = (biomeLinks[currentBiome] as (Biome | [Biome, integer])[])
+        biomes = (biomeLinks[currentBiome] as (Biome | [Biome, number])[])
           .filter(b => !Array.isArray(b) || !Utils.randSeedInt(b[1]))
           .map(b => !Array.isArray(b) ? b : b[0]);
       }, this.scene.currentBattle.waveIndex);
@@ -46,7 +46,7 @@ export class SelectBiomePhase extends BattlePhase {
         this.scene.executeWithSeedOffset(() => {
           biomeChoices = (!Array.isArray(biomeLinks[currentBiome])
             ? [ biomeLinks[currentBiome] as Biome ]
-            : biomeLinks[currentBiome] as (Biome | [Biome, integer])[])
+            : biomeLinks[currentBiome] as (Biome | [Biome, number])[])
             .filter((b, i) => !Array.isArray(b) || !Utils.randSeedInt(b[1]))
             .map(b => Array.isArray(b) ? b[0] : b);
         }, this.scene.currentBattle.waveIndex);
diff --git a/src/phases/select-modifier-phase.ts b/src/phases/select-modifier-phase.ts
index 98975e30720..972e187dbab 100644
--- a/src/phases/select-modifier-phase.ts
+++ b/src/phases/select-modifier-phase.ts
@@ -13,14 +13,14 @@ import { CustomModifierSettings } from "#app/modifier/modifier-type";
 import { isNullOrUndefined, NumberHolder } from "#app/utils";
 
 export class SelectModifierPhase extends BattlePhase {
-  private rerollCount: integer;
+  private rerollCount: number;
   private modifierTiers?: ModifierTier[];
   private customModifierSettings?: CustomModifierSettings;
   private isCopy: boolean;
 
   private typeOptions: ModifierTypeOption[];
 
-  constructor(scene: BattleScene, rerollCount: integer = 0, modifierTiers?: ModifierTier[], customModifierSettings?: CustomModifierSettings, isCopy: boolean = false) {
+  constructor(scene: BattleScene, rerollCount: number = 0, modifierTiers?: ModifierTier[], customModifierSettings?: CustomModifierSettings, isCopy: boolean = false) {
     super(scene);
 
     this.rerollCount = rerollCount;
@@ -42,7 +42,7 @@ export class SelectModifierPhase extends BattlePhase {
     if (!this.isCopy) {
       regenerateModifierPoolThresholds(party, this.getPoolType(), this.rerollCount);
     }
-    const modifierCount = new Utils.IntegerHolder(3);
+    const modifierCount = new Utils.NumberHolder(3);
     if (this.isPlayer()) {
       this.scene.applyModifiers(ExtraModifierModifier, true, modifierCount);
       this.scene.applyModifiers(TempExtraModifierModifier, true, modifierCount);
@@ -63,7 +63,7 @@ export class SelectModifierPhase extends BattlePhase {
 
     this.typeOptions = this.getModifierTypeOptions(modifierCount.value);
 
-    const modifierSelectCallback = (rowCursor: integer, cursor: integer) => {
+    const modifierSelectCallback = (rowCursor: number, cursor: number) => {
       if (rowCursor < 0 || cursor < 0) {
         this.scene.ui.showText(i18next.t("battle:skipItemQuestion"), null, () => {
           this.scene.ui.setOverlayMode(Mode.CONFIRM, () => {
@@ -75,7 +75,7 @@ export class SelectModifierPhase extends BattlePhase {
         return false;
       }
       let modifierType: ModifierType;
-      let cost: integer;
+      let cost: number;
       const rerollCost = this.getRerollCost(this.scene.lockModifierTiers);
       switch (rowCursor) {
         case 0:
@@ -98,7 +98,7 @@ export class SelectModifierPhase extends BattlePhase {
               }
               break;
             case 1:
-              this.scene.ui.setModeWithoutClear(Mode.PARTY, PartyUiMode.MODIFIER_TRANSFER, -1, (fromSlotIndex: integer, itemIndex: integer, itemQuantity: integer, toSlotIndex: integer) => {
+              this.scene.ui.setModeWithoutClear(Mode.PARTY, PartyUiMode.MODIFIER_TRANSFER, -1, (fromSlotIndex: number, itemIndex: number, itemQuantity: number, toSlotIndex: number) => {
                 if (toSlotIndex !== undefined && fromSlotIndex < 6 && toSlotIndex < 6 && fromSlotIndex !== toSlotIndex && itemIndex > -1) {
                   const itemModifiers = this.scene.findModifiers(m => m instanceof PokemonHeldItemModifier
                       && m.isTransferable && m.pokemonId === party[fromSlotIndex].id) as PokemonHeldItemModifier[];
@@ -197,7 +197,7 @@ export class SelectModifierPhase extends BattlePhase {
 
       if (modifierType! instanceof PokemonModifierType) { //TODO: is the bang correct?
         if (modifierType instanceof FusePokemonModifierType) {
-          this.scene.ui.setModeWithoutClear(Mode.PARTY, PartyUiMode.SPLICE, -1, (fromSlotIndex: integer, spliceSlotIndex: integer) => {
+          this.scene.ui.setModeWithoutClear(Mode.PARTY, PartyUiMode.SPLICE, -1, (fromSlotIndex: number, spliceSlotIndex: number) => {
             if (spliceSlotIndex !== undefined && fromSlotIndex < 6 && spliceSlotIndex < 6 && fromSlotIndex !== spliceSlotIndex) {
               this.scene.ui.setMode(Mode.MODIFIER_SELECT, this.isPlayer()).then(() => {
                 const modifier = modifierType.newModifier(party[fromSlotIndex], party[spliceSlotIndex])!; //TODO: is the bang correct?
@@ -220,13 +220,13 @@ export class SelectModifierPhase extends BattlePhase {
           const tmMoveId = isTmModifier
             ? (modifierType as TmModifierType).moveId
             : undefined;
-          this.scene.ui.setModeWithoutClear(Mode.PARTY, partyUiMode, -1, (slotIndex: integer, option: PartyOption) => {
+          this.scene.ui.setModeWithoutClear(Mode.PARTY, partyUiMode, -1, (slotIndex: number, option: PartyOption) => {
             if (slotIndex < 6) {
               this.scene.ui.setMode(Mode.MODIFIER_SELECT, this.isPlayer()).then(() => {
                 const modifier = !isMoveModifier
                   ? !isRememberMoveModifier
                     ? modifierType.newModifier(party[slotIndex])
-                    : modifierType.newModifier(party[slotIndex], option as integer)
+                    : modifierType.newModifier(party[slotIndex], option as number)
                   : modifierType.newModifier(party[slotIndex], option - PartyOption.MOVE_1);
                 applyModifier(modifier!, true); // TODO: is the bang correct?
               });
@@ -288,7 +288,7 @@ export class SelectModifierPhase extends BattlePhase {
     return ModifierPoolType.PLAYER;
   }
 
-  getModifierTypeOptions(modifierCount: integer): ModifierTypeOption[] {
+  getModifierTypeOptions(modifierCount: number): ModifierTypeOption[] {
     return getPlayerModifierTypeOptions(modifierCount, this.scene.getPlayerParty(), this.scene.lockModifierTiers ? this.modifierTiers : undefined, this.customModifierSettings);
   }
 
diff --git a/src/phases/select-starter-phase.ts b/src/phases/select-starter-phase.ts
index 2273ab1cd3c..83ffee01e1b 100644
--- a/src/phases/select-starter-phase.ts
+++ b/src/phases/select-starter-phase.ts
@@ -26,7 +26,7 @@ export class SelectStarterPhase extends Phase {
 
     this.scene.ui.setMode(Mode.STARTER_SELECT, (starters: Starter[]) => {
       this.scene.ui.clearText();
-      this.scene.ui.setMode(Mode.SAVE_SLOT, SaveSlotUiMode.SAVE, (slotId: integer) => {
+      this.scene.ui.setMode(Mode.SAVE_SLOT, SaveSlotUiMode.SAVE, (slotId: number) => {
         if (slotId === -1) {
           this.scene.clearPhaseQueue();
           this.scene.pushPhase(new TitlePhase(this.scene));
@@ -45,7 +45,7 @@ export class SelectStarterPhase extends Phase {
   initBattle(starters: Starter[]) {
     const party = this.scene.getPlayerParty();
     const loadPokemonAssets: Promise<void>[] = [];
-    starters.forEach((starter: Starter, i: integer) => {
+    starters.forEach((starter: Starter, i: number) => {
       if (!i && Overrides.STARTER_SPECIES_OVERRIDE) {
         starter.species = getPokemonSpecies(Overrides.STARTER_SPECIES_OVERRIDE as Species);
       }
diff --git a/src/phases/select-target-phase.ts b/src/phases/select-target-phase.ts
index 6f11f984c4b..1fed6aeff35 100644
--- a/src/phases/select-target-phase.ts
+++ b/src/phases/select-target-phase.ts
@@ -8,7 +8,7 @@ import i18next from "#app/plugins/i18n";
 import { allMoves } from "#app/data/move";
 
 export class SelectTargetPhase extends PokemonPhase {
-  constructor(scene: BattleScene, fieldIndex: integer) {
+  constructor(scene: BattleScene, fieldIndex: number) {
     super(scene, fieldIndex);
   }
 
diff --git a/src/phases/show-party-exp-bar-phase.ts b/src/phases/show-party-exp-bar-phase.ts
index f1783e7715f..0cdc660d701 100644
--- a/src/phases/show-party-exp-bar-phase.ts
+++ b/src/phases/show-party-exp-bar-phase.ts
@@ -10,7 +10,7 @@ import { PlayerPartyMemberPokemonPhase } from "./player-party-member-pokemon-pha
 export class ShowPartyExpBarPhase extends PlayerPartyMemberPokemonPhase {
   private expValue: number;
 
-  constructor(scene: BattleScene, partyMemberIndex: integer, expValue: number) {
+  constructor(scene: BattleScene, partyMemberIndex: number, expValue: number) {
     super(scene, partyMemberIndex);
 
     this.expValue = expValue;
diff --git a/src/phases/stat-stage-change-phase.ts b/src/phases/stat-stage-change-phase.ts
index ce6ebea2442..892cb94e486 100644
--- a/src/phases/stat-stage-change-phase.ts
+++ b/src/phases/stat-stage-change-phase.ts
@@ -16,14 +16,14 @@ export type StatStageChangeCallback = (target: Pokemon | null, changed: BattleSt
 export class StatStageChangePhase extends PokemonPhase {
   private stats: BattleStat[];
   private selfTarget: boolean;
-  private stages: integer;
+  private stages: number;
   private showMessage: boolean;
   private ignoreAbilities: boolean;
   private canBeCopied: boolean;
   private onChange: StatStageChangeCallback | null;
 
 
-  constructor(scene: BattleScene, battlerIndex: BattlerIndex, selfTarget: boolean, stats: BattleStat[], stages: integer, showMessage: boolean = true, ignoreAbilities: boolean = false, canBeCopied: boolean = true, onChange: StatStageChangeCallback | null = null) {
+  constructor(scene: BattleScene, battlerIndex: BattlerIndex, selfTarget: boolean, stats: BattleStat[], stages: number, showMessage: boolean = true, ignoreAbilities: boolean = false, canBeCopied: boolean = true, onChange: StatStageChangeCallback | null = null) {
     super(scene, battlerIndex);
 
     this.selfTarget = selfTarget;
@@ -214,7 +214,7 @@ export class StatStageChangePhase extends PokemonPhase {
     }
   }
 
-  getStatStageChangeMessages(stats: BattleStat[], stages: integer, relStages: integer[]): string[] {
+  getStatStageChangeMessages(stats: BattleStat[], stages: number, relStages: number[]): string[] {
     const messages: string[] = [];
 
     const relStageStatIndexes = {};
diff --git a/src/phases/summon-missing-phase.ts b/src/phases/summon-missing-phase.ts
index 83ac8779dd8..6fb2cc71c94 100644
--- a/src/phases/summon-missing-phase.ts
+++ b/src/phases/summon-missing-phase.ts
@@ -4,7 +4,7 @@ import i18next from "i18next";
 import { SummonPhase } from "./summon-phase";
 
 export class SummonMissingPhase extends SummonPhase {
-  constructor(scene: BattleScene, fieldIndex: integer) {
+  constructor(scene: BattleScene, fieldIndex: number) {
     super(scene, fieldIndex);
   }
 
diff --git a/src/phases/summon-phase.ts b/src/phases/summon-phase.ts
index 119e550293c..eaac4fe2eea 100644
--- a/src/phases/summon-phase.ts
+++ b/src/phases/summon-phase.ts
@@ -17,7 +17,7 @@ import { MysteryEncounterMode } from "#enums/mystery-encounter-mode";
 export class SummonPhase extends PartyMemberPokemonPhase {
   private loaded: boolean;
 
-  constructor(scene: BattleScene, fieldIndex: integer, player: boolean = true, loaded: boolean = false) {
+  constructor(scene: BattleScene, fieldIndex: number, player: boolean = true, loaded: boolean = false) {
     super(scene, fieldIndex, player);
 
     this.loaded = loaded;
diff --git a/src/phases/switch-phase.ts b/src/phases/switch-phase.ts
index 2abb109a529..ff0ccace632 100644
--- a/src/phases/switch-phase.ts
+++ b/src/phases/switch-phase.ts
@@ -10,7 +10,7 @@ import { SwitchSummonPhase } from "./switch-summon-phase";
  * for the player (if a switch would be valid for the current battle state).
  */
 export class SwitchPhase extends BattlePhase {
-  protected readonly fieldIndex: integer;
+  protected readonly fieldIndex: number;
   private readonly switchType: SwitchType;
   private readonly isModal: boolean;
   private readonly doReturn: boolean;
@@ -25,7 +25,7 @@ export class SwitchPhase extends BattlePhase {
      * @param doReturn Indicates if the party member on the field should be
      * recalled to ball or has already left the field. Passed to {@linkcode SwitchSummonPhase}.
      */
-  constructor(scene: BattleScene, switchType: SwitchType, fieldIndex: integer, isModal: boolean, doReturn: boolean) {
+  constructor(scene: BattleScene, switchType: SwitchType, fieldIndex: number, isModal: boolean, doReturn: boolean) {
     super(scene);
 
     this.switchType = switchType;
@@ -61,7 +61,7 @@ export class SwitchPhase extends BattlePhase {
     // Override field index to 0 in case of double battle where 2/3 remaining legal party members fainted at once
     const fieldIndex = this.scene.currentBattle.getBattlerCount() === 1 || this.scene.getPokemonAllowedInBattle().length > 1 ? this.fieldIndex : 0;
 
-    this.scene.ui.setMode(Mode.PARTY, this.isModal ? PartyUiMode.FAINT_SWITCH : PartyUiMode.POST_BATTLE_SWITCH, fieldIndex, (slotIndex: integer, option: PartyOption) => {
+    this.scene.ui.setMode(Mode.PARTY, this.isModal ? PartyUiMode.FAINT_SWITCH : PartyUiMode.POST_BATTLE_SWITCH, fieldIndex, (slotIndex: number, option: PartyOption) => {
       if (slotIndex >= this.scene.currentBattle.getBattlerCount() && slotIndex < 6) {
         const switchType = (option === PartyOption.PASS_BATON) ? SwitchType.BATON_PASS : this.switchType;
         this.scene.unshiftPhase(new SwitchSummonPhase(this.scene, switchType, fieldIndex, slotIndex, this.doReturn));
diff --git a/src/phases/switch-summon-phase.ts b/src/phases/switch-summon-phase.ts
index 36db8b7a7e7..0838eac77da 100644
--- a/src/phases/switch-summon-phase.ts
+++ b/src/phases/switch-summon-phase.ts
@@ -16,7 +16,7 @@ import { SwitchType } from "#enums/switch-type";
 
 export class SwitchSummonPhase extends SummonPhase {
   private readonly switchType: SwitchType;
-  private readonly slotIndex: integer;
+  private readonly slotIndex: number;
   private readonly doReturn: boolean;
 
   private lastPokemon: Pokemon;
@@ -25,12 +25,12 @@ export class SwitchSummonPhase extends SummonPhase {
      * Constructor for creating a new SwitchSummonPhase
      * @param scene {@linkcode BattleScene} the scene the phase is associated with
      * @param switchType the type of switch behavior
-     * @param fieldIndex integer representing position on the battle field
-     * @param slotIndex integer for the index of pokemon (in party of 6) to switch into
+     * @param fieldIndex number representing position on the battle field
+     * @param slotIndex number for the index of pokemon (in party of 6) to switch into
      * @param doReturn boolean whether to render "comeback" dialogue
      * @param player boolean if the switch is from the player
      */
-  constructor(scene: BattleScene, switchType: SwitchType, fieldIndex: integer, slotIndex: integer, doReturn: boolean, player?: boolean) {
+  constructor(scene: BattleScene, switchType: SwitchType, fieldIndex: number, slotIndex: number, doReturn: boolean, player?: boolean) {
     super(scene, fieldIndex, player !== undefined ? player : true);
 
     this.switchType = switchType;
diff --git a/src/phases/test-message-phase.ts b/src/phases/test-message-phase.ts
deleted file mode 100644
index 464a5ed1f94..00000000000
--- a/src/phases/test-message-phase.ts
+++ /dev/null
@@ -1,8 +0,0 @@
-import BattleScene from "#app/battle-scene";
-import { MessagePhase } from "./message-phase";
-
-export class TestMessagePhase extends MessagePhase {
-  constructor(scene: BattleScene, message: string) {
-    super(scene, message, null, true);
-  }
-}
diff --git a/src/phases/title-phase.ts b/src/phases/title-phase.ts
index 88793617776..220a2da5256 100644
--- a/src/phases/title-phase.ts
+++ b/src/phases/title-phase.ts
@@ -1,6 +1,5 @@
 import { loggedInUser } from "#app/account";
 import { BattleType } from "#app/battle";
-import BattleScene from "#app/battle-scene";
 import { fetchDailyRunSeed, getDailyRunStarters } from "#app/data/daily-run";
 import { Gender } from "#app/data/gender";
 import { getBiomeKey } from "#app/field/arena";
@@ -24,16 +23,10 @@ import { SummonPhase } from "./summon-phase";
 
 
 export class TitlePhase extends Phase {
-  private loaded: boolean;
+  private loaded: boolean = false;
   private lastSessionData: SessionSaveData;
   public gameMode: GameModes;
 
-  constructor(scene: BattleScene) {
-    super(scene);
-
-    this.loaded = false;
-  }
-
   start(): void {
     super.start();
 
@@ -133,7 +126,7 @@ export class TitlePhase extends Phase {
       label: i18next.t("menu:loadGame"),
       handler: () => {
         this.scene.ui.setOverlayMode(Mode.SAVE_SLOT, SaveSlotUiMode.LOAD,
-          (slotId: integer) => {
+          (slotId: number) => {
             if (slotId === -1) {
               return this.showOptions();
             }
@@ -166,7 +159,7 @@ export class TitlePhase extends Phase {
     this.scene.ui.setMode(Mode.TITLE, config);
   }
 
-  loadSaveSlot(slotId: integer): void {
+  loadSaveSlot(slotId: number): void {
     this.scene.sessionSlotId = slotId > -1 || !loggedInUser ? slotId : loggedInUser.lastSessionSlot;
     this.scene.ui.setMode(Mode.MESSAGE);
     this.scene.ui.resetModeChain();
@@ -184,7 +177,7 @@ export class TitlePhase extends Phase {
   }
 
   initDailyRun(): void {
-    this.scene.ui.setMode(Mode.SAVE_SLOT, SaveSlotUiMode.SAVE, (slotId: integer) => {
+    this.scene.ui.setMode(Mode.SAVE_SLOT, SaveSlotUiMode.SAVE, (slotId: number) => {
       this.scene.clearPhaseQueue();
       if (slotId === -1) {
         this.scene.pushPhase(new TitlePhase(this.scene));
diff --git a/src/phases/trainer-message-test-phase.ts b/src/phases/trainer-message-test-phase.ts
deleted file mode 100644
index d9e58473bd5..00000000000
--- a/src/phases/trainer-message-test-phase.ts
+++ /dev/null
@@ -1,41 +0,0 @@
-import BattleScene from "#app/battle-scene";
-import { trainerConfigs } from "#app/data/trainer-config";
-import { TrainerType } from "#app/enums/trainer-type";
-import { BattlePhase } from "./battle-phase";
-import { TestMessagePhase } from "./test-message-phase";
-
-export class TrainerMessageTestPhase extends BattlePhase {
-  private trainerTypes: TrainerType[];
-
-  constructor(scene: BattleScene, ...trainerTypes: TrainerType[]) {
-    super(scene);
-
-    this.trainerTypes = trainerTypes;
-  }
-
-  start() {
-    super.start();
-
-    const testMessages: string[] = [];
-
-    for (const t of Object.keys(trainerConfigs)) {
-      const type = parseInt(t);
-      if (this.trainerTypes.length && !this.trainerTypes.find(tt => tt === type as TrainerType)) {
-        continue;
-      }
-      const config = trainerConfigs[type];
-      [ config.encounterMessages, config.femaleEncounterMessages, config.victoryMessages, config.femaleVictoryMessages, config.defeatMessages, config.femaleDefeatMessages ]
-        .map(messages => {
-          if (messages?.length) {
-            testMessages.push(...messages);
-          }
-        });
-    }
-
-    for (const message of testMessages) {
-      this.scene.pushPhase(new TestMessagePhase(this.scene, message));
-    }
-
-    this.end();
-  }
-}
diff --git a/src/phases/turn-init-phase.ts b/src/phases/turn-init-phase.ts
index baff6c7d73f..cc4926d7f4d 100644
--- a/src/phases/turn-init-phase.ts
+++ b/src/phases/turn-init-phase.ts
@@ -44,7 +44,6 @@ export class TurnInitPhase extends FieldPhase {
       }
     });
 
-    //this.scene.pushPhase(new MoveAnimTestPhase(this.scene));
     this.scene.eventTarget.dispatchEvent(new TurnInitEvent());
 
     handleMysteryEncounterBattleStartEffects(this.scene);
diff --git a/src/phases/turn-start-phase.ts b/src/phases/turn-start-phase.ts
index dc3ee3f660a..ea3d7763eba 100644
--- a/src/phases/turn-start-phase.ts
+++ b/src/phases/turn-start-phase.ts
@@ -99,8 +99,8 @@ export class TurnStartPhase extends FieldPhase {
         const bMove = allMoves[bCommand!.move!.move];
 
         // The game now considers priority and applies the relevant move and ability attributes
-        const aPriority = new Utils.IntegerHolder(aMove.priority);
-        const bPriority = new Utils.IntegerHolder(bMove.priority);
+        const aPriority = new Utils.NumberHolder(aMove.priority);
+        const bPriority = new Utils.NumberHolder(bMove.priority);
 
         applyMoveAttrs(IncrementMovePriorityAttr, this.scene.getField().find(p => p?.isActive() && p.getBattlerIndex() === a)!, null, aMove, aPriority);
         applyMoveAttrs(IncrementMovePriorityAttr, this.scene.getField().find(p => p?.isActive() && p.getBattlerIndex() === b)!, null, bMove, bPriority);
diff --git a/src/phases/victory-phase.ts b/src/phases/victory-phase.ts
index 1faa31655df..46d7a916296 100644
--- a/src/phases/victory-phase.ts
+++ b/src/phases/victory-phase.ts
@@ -16,7 +16,7 @@ export class VictoryPhase extends PokemonPhase {
   /** If true, indicates that the phase is intended for EXP purposes only, and not to continue a battle to next phase */
   isExpOnly: boolean;
 
-  constructor(scene: BattleScene, battlerIndex: BattlerIndex | integer, isExpOnly: boolean = false) {
+  constructor(scene: BattleScene, battlerIndex: BattlerIndex | number, isExpOnly: boolean = false) {
     super(scene, battlerIndex);
 
     this.isExpOnly = isExpOnly;
diff --git a/src/phases/weather-effect-phase.ts b/src/phases/weather-effect-phase.ts
index b48ee342780..2e7af91a849 100644
--- a/src/phases/weather-effect-phase.ts
+++ b/src/phases/weather-effect-phase.ts
@@ -21,8 +21,7 @@ export class WeatherEffectPhase extends CommonAnimPhase {
     this.weather = this.scene?.arena?.weather;
 
     if (!this.weather) {
-      this.end();
-      return;
+      return this.end();
     }
 
     this.setAnimation(CommonAnim.SUNNY + (this.weather.weatherType - 1));
@@ -46,7 +45,7 @@ export class WeatherEffectPhase extends CommonAnimPhase {
 
           const damage = Utils.toDmgValue(pokemon.getMaxHp() / 16);
 
-          this.scene.queueMessage(getWeatherDamageMessage(this.weather?.weatherType!, pokemon)!); // TODO: are those bangs correct?
+          this.scene.queueMessage(getWeatherDamageMessage(this.weather!.weatherType, pokemon) ?? "");
           pokemon.damageAndUpdate(damage, HitResult.EFFECTIVE, false, false, true);
         };
 
@@ -59,7 +58,7 @@ export class WeatherEffectPhase extends CommonAnimPhase {
       }
     }
 
-    this.scene.ui.showText(getWeatherLapseMessage(this.weather.weatherType)!, null, () => { // TODO: is this bang correct?
+    this.scene.ui.showText(getWeatherLapseMessage(this.weather.weatherType) ?? "", null, () => {
       this.executeForAll((pokemon: Pokemon) => applyPostWeatherLapseAbAttrs(PostWeatherLapseAbAttr, pokemon, this.weather));
 
       super.start();