diff --git a/src/core/game-host.ts b/src/core/game-host.ts
index 625dce4..d811ca6 100644
--- a/src/core/game-host.ts
+++ b/src/core/game-host.ts
@@ -1,29 +1,28 @@
-import { ReadonlySignal, Signal } from "@preact/signals-core";
 import { createPromptContext } from "@/utils/command";
-import { createGameContext, IGameContext } from "./game";
 import { PromptContext } from "@/utils/command/command-prompt";
+import { ReadonlySignal, Signal } from "@preact/signals-core";
+import { createGameContext, IGameContext } from "./game";
 
 export type GameHostStatus = "created" | "running" | "disposed";
 
-export class GameHost<TModule extends GameModule> {
-  readonly state: ReadonlySignal<GameState<TModule>>;
+export class GameHost<
+  TState extends Record<string, unknown>,
+  TResult = unknown,
+  TModule extends GameModule<TState, TResult> = GameModule<TState, TResult>,
+> {
+  readonly state: ReadonlySignal<TState>;
   readonly status: ReadonlySignal<GameHostStatus>;
   readonly prompts: PromptContext;
 
-  private _context: IGameContext<GameState<TModule>>;
-  private _start: (
-    ctx: IGameContext<GameState<TModule>>,
-  ) => Promise<GameResult<TModule>>;
+  private _context: IGameContext<TState>;
+  private _start: (ctx: IGameContext<TState>) => Promise<TResult>;
   private _status: Signal<GameHostStatus>;
-  private _createInitialState: () => GameState<TModule>;
+  private _createInitialState: () => TState;
   private _eventListeners: Map<"start" | "dispose", Set<() => void>>;
   private _isDisposed = false;
 
   constructor(public readonly gameModule: TModule) {
-    const { createInitialState, start } = gameModule as unknown as GameModule<
-      GameState<TModule>,
-      GameResult<TModule>
-    >;
+    const { createInitialState, start } = gameModule;
     this._createInitialState = createInitialState;
     this._eventListeners = new Map();
 
@@ -53,7 +52,7 @@ export class GameHost<TModule extends GameModule> {
     this._context._state.clearInterruptions();
   }
 
-  start(seed?: number): Promise<GameResult<TModule>> {
+  start(seed?: number): Promise<TResult> {
     if (this._isDisposed) {
       throw new Error("GameHost is disposed");
     }
@@ -115,15 +114,11 @@ export type GameModule<
   createInitialState: () => TState;
   start: (ctx: IGameContext<TState>) => Promise<TResult>;
 };
-export type GameState<TModule extends GameModule> = ReturnType<
-  TModule["createInitialState"]
->;
-export type GameResult<TModule extends GameModule> = Awaited<
-  ReturnType<TModule["start"]>
->;
 
-export function createGameHost<TModule extends GameModule>(
-  gameModule: TModule,
-): GameHost<TModule> {
+export function createGameHost<
+  TState extends Record<string, unknown> = Record<string, unknown>,
+  TResult = unknown,
+  TModule extends GameModule<TState, TResult> = GameModule<TState, TResult>,
+>(gameModule: TModule): GameHost<TState, TResult, TModule> {
   return new GameHost(gameModule);
 }
diff --git a/src/index.ts b/src/index.ts
index 603a531..2d411d1 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -7,13 +7,7 @@
 export type { IGameContext } from "./core/game";
 export { createPromptDef } from "./core/game";
 
-export type {
-  GameHost,
-  GameHostStatus,
-  GameModule,
-  GameState,
-  GameResult,
-} from "./core/game-host";
+export type { GameHost, GameHostStatus, GameModule } from "./core/game-host";
 export { createGameHost } from "./core/game-host";
 
 export type { Part } from "./core/part";