diff --git a/build/html.ts b/build/html.ts
index 4577f6d..b64ee2f 100644
--- a/build/html.ts
+++ b/build/html.ts
@@ -70,6 +70,10 @@ function connect() {
 connect();
 </script>`;
 
+const POLYFILL = `<script>
+if (!Symbol.metadata) Symbol.metadata = Symbol.for('Symbol.metadata');
+</script>`;
+
 async function buildBundle(game: string, production: boolean) {
     const assetsDir = path.resolve(import.meta.dir, 'assets');
     const srcDir = path.resolve(import.meta.dir, '..', 'src');
@@ -188,7 +192,7 @@ export async function buildHTML(game: string, {
         }
 
         script = script.replaceAll('await Promise.resolve().then(() =>', '(');
-        let scriptPrefix = '';
+        let scriptPrefix = POLYFILL;
         if (production) {
             const minifyResult = UglifyJS.minify(script, {
                 module: true,
@@ -201,7 +205,7 @@ export async function buildHTML(game: string, {
             }
         } else if (mobile) {
             const eruda = await Bun.file(path.resolve(import.meta.dir, '..', 'node_modules', 'eruda', 'eruda.js')).text();
-            scriptPrefix = `<script>${eruda};\neruda.init();</script>`;
+            scriptPrefix += `<script>${eruda};\neruda.init();</script>`;
         }
         if (!local) {
             scriptPrefix += SW_SCRIPT;
diff --git a/src/common/rpg/components/entity.ts b/src/common/rpg/components/entity.ts
new file mode 100644
index 0000000..78e102c
--- /dev/null
+++ b/src/common/rpg/components/entity.ts
@@ -0,0 +1,74 @@
+import type { RPGActions, RPGVariables } from "../types";
+import { ACTION_KEYS, VARIABLE_KEYS } from "../decorators";
+
+export interface RPGComponent {
+    getVariables: () => RPGVariables;
+    getActions: () => RPGActions;
+}
+
+export abstract class RPGComponentBase implements RPGComponent {
+    getVariables(): RPGVariables {
+        const meta = (this.constructor as Function)[Symbol.metadata];
+        const keys = meta?.[VARIABLE_KEYS] as Map<string | symbol, string> | undefined;
+        if (!keys) return {};
+        const vars: RPGVariables = {};
+        for (const [methodKey, exportName] of keys) {
+            const k = String(methodKey);
+            const v = (this as unknown as Record<string, RPGVariables[string]>)[k];
+            if (v != null) {
+                vars[exportName] = v;
+            }
+        }
+        return vars;
+    }
+
+    getActions(): RPGActions {
+        const meta = (this.constructor as Function)[Symbol.metadata];
+        const keys = meta?.[ACTION_KEYS] as Set<string | symbol> | undefined;
+        if (!keys) return {};
+        const actions: RPGActions = {};
+        for (const key of keys) {
+            const k = String(key);
+            actions[k] = (arg?: unknown) => (this as unknown as Record<string, (a?: unknown) => unknown>)[k](arg);
+        }
+        return actions;
+    }
+}
+
+export class RPGEntity implements RPGComponent {
+    private components = new Map<string, RPGComponent>();
+
+    addComponent(id: string, component: RPGComponent): void {
+        this.components.set(id, component);
+    }
+
+    removeComponent(id: string): void {
+        this.components.delete(id);
+    }
+
+    getComponent<T extends RPGComponent>(id: string): T | undefined {
+        return this.components.get(id) as T | undefined;
+    }
+
+    getVariables(): RPGVariables {
+        const variables: RPGVariables = {};
+        for (const [componentKey, component] of this.components) {
+            for (const [key, value] of Object.entries(component.getVariables())) {
+                if (value != null) {
+                    variables[`${componentKey}.${key}`] = value;
+                }
+            }
+        }
+        return variables;
+    }
+
+    getActions() {
+        const actions: RPGActions = {};
+        for (const [componentKey, component] of this.components) {
+            for (const [key, action] of Object.entries(component.getActions())) {
+                actions[`${componentKey}.${key}`] = action;
+            }
+        }
+        return actions;
+    }
+}
\ No newline at end of file
diff --git a/src/common/rpg/inventory.ts b/src/common/rpg/components/inventory.ts
similarity index 89%
rename from src/common/rpg/inventory.ts
rename to src/common/rpg/components/inventory.ts
index fce9586..9e30421 100644
--- a/src/common/rpg/inventory.ts
+++ b/src/common/rpg/components/inventory.ts
@@ -1,16 +1,24 @@
-import type { InventoryOptions, InventorySlotInput, SlotId } from "./types";
+import type { InventoryOptions, InventorySlotInput, SlotId } from "../types";
+import { action } from "../decorators";
+import { RPGComponentBase } from "./entity";
 
 interface SlotEntry {
     readonly slotId: SlotId;
     readonly limit: number | undefined;
     state: { itemId: string; amount: number } | null;
 }
+interface SlotUpdateArgs {
+    itemId: string;
+    amount: number;
+    slotId?: SlotId;
+}
 
-export class Inventory {
+export class Inventory extends RPGComponentBase {
     private readonly slots: Map<SlotId, SlotEntry>;
     private readonly maxAmountPerItem: Record<string, number>;
 
     constructor(slotDefs: Array<InventorySlotInput>, options?: InventoryOptions) {
+        super();
         this.slots = new Map(
             slotDefs.map(def => {
                 const slotId = typeof def === 'object' ? def.slotId : def;
@@ -34,7 +42,8 @@ export class Inventory {
         return this.slotCapFor(slot, itemId) - (slot.state?.amount ?? 0);
     }
 
-    addItem(itemId: string, amount: number, slotId?: SlotId): boolean {
+    @action
+    addItem({ itemId, amount, slotId }: SlotUpdateArgs): boolean {
         if (amount < 0) return false;
         if (amount === 0) return true;
 
@@ -78,7 +87,8 @@ export class Inventory {
         return remaining === 0;
     }
 
-    removeItem(itemId: string, amount: number, slotId?: SlotId): boolean {
+    @action
+    removeItem({ itemId, amount, slotId }: SlotUpdateArgs): boolean {
         if (amount < 0) return false;
         if (amount === 0) return true;
 
@@ -129,11 +139,7 @@ export class Inventory {
         return result;
     }
 
-    getVariables(): Record<string, number> {
-        const result: Record<string, number> = {};
-        for (const [itemId, amount] of this.getItems()) {
-            result[`inventory.${itemId}`] = amount;
-        }
-        return result;
+    override getVariables(): Record<string, number> {
+        return Object.fromEntries(this.getItems());
     }
 }
diff --git a/src/common/rpg/components/stat.ts b/src/common/rpg/components/stat.ts
new file mode 100644
index 0000000..116e01d
--- /dev/null
+++ b/src/common/rpg/components/stat.ts
@@ -0,0 +1,21 @@
+import { action, variable } from "../decorators";
+import { RPGComponentBase } from "./entity";
+
+export class Stat extends RPGComponentBase {
+    @variable private value: number;
+    @variable private maxValue: number | undefined;
+
+    constructor(value: number, maxValue?: number) {
+        super();
+        this.value = value;
+        this.maxValue = maxValue;
+    }
+
+    @action
+    update(amount: number) {
+        this.value = Math.max(0, this.value + amount);
+        if (this.maxValue) {
+            this.value = Math.min(this.value, this.maxValue);
+        }
+    }
+}
diff --git a/src/common/rpg/components/variables.ts b/src/common/rpg/components/variables.ts
new file mode 100644
index 0000000..308f605
--- /dev/null
+++ b/src/common/rpg/components/variables.ts
@@ -0,0 +1,37 @@
+import type { RPGVariables } from "../types";
+import { action } from "../decorators";
+import { RPGComponentBase } from "./entity";
+
+interface Var {
+    key: string;
+    value: RPGVariables[string];
+}
+
+export class Variables extends RPGComponentBase {
+    private readonly variables: RPGVariables = {};
+
+    override getVariables() {
+        return this.variables;
+    }
+
+    @action
+    set({ key, value }: Var) {
+        this.variables[key] = value;
+        return this.variables;
+    }
+
+    @action
+    unset(key: string) {
+        delete this.variables[key];
+        return this.variables;
+    }
+
+    @action
+    increment({ key, value }: Var) {
+        const currentValue = this.variables[key] ?? 0;
+        if (typeof currentValue === 'number' && typeof value === 'number') {
+            this.variables[key] = currentValue + value;
+        }
+        return this.variables;
+    }
+}
diff --git a/src/common/rpg/decorators.ts b/src/common/rpg/decorators.ts
new file mode 100644
index 0000000..386c007
--- /dev/null
+++ b/src/common/rpg/decorators.ts
@@ -0,0 +1,38 @@
+import type { RPGVariables } from "./types";
+
+export const ACTION_KEYS = Symbol('rpg.actions');
+export const VARIABLE_KEYS = Symbol('rpg.variables');
+
+export function action<T extends (arg?: any) => unknown>(
+    target: T,
+    context: ClassMethodDecoratorContext<unknown, T>
+): T {
+    const prev = context.metadata[ACTION_KEYS] as Set<string | symbol> | undefined;
+    context.metadata[ACTION_KEYS] = new Set(prev).add(context.name);
+    return target;
+}
+
+type VariableContext<T extends RPGVariables[string]> =
+    | ClassFieldDecoratorContext<unknown, T>
+    | ClassGetterDecoratorContext<unknown, T>;
+
+function registerVariable(context: VariableContext<RPGVariables[string]>, exportName: string): void {
+    const prev = context.metadata[VARIABLE_KEYS] as Map<string | symbol, string> | undefined;
+    context.metadata[VARIABLE_KEYS] = new Map(prev).set(context.name, exportName);
+}
+
+export function variable(name: string): <T extends RPGVariables[string]>(target: undefined | (() => T), context: VariableContext<T>) => void;
+export function variable<T extends RPGVariables[string]>(target: undefined, context: ClassFieldDecoratorContext<unknown, T>): void;
+export function variable<T extends RPGVariables[string]>(target: () => T, context: ClassGetterDecoratorContext<unknown, T>): void;
+export function variable(
+    nameOrTarget: string | undefined | (() => RPGVariables[string]),
+    context?: VariableContext<RPGVariables[string]>
+): unknown {
+    if (typeof nameOrTarget === 'string') {
+        const exportName = nameOrTarget;
+        return (_target: unknown, ctx: VariableContext<RPGVariables[string]>) => {
+            registerVariable(ctx, exportName);
+        };
+    }
+    registerVariable(context!, String(context!.name));
+}
diff --git a/src/common/rpg/quest.ts b/src/common/rpg/quest.ts
index aecb904..70e5b98 100644
--- a/src/common/rpg/quest.ts
+++ b/src/common/rpg/quest.ts
@@ -1,4 +1,6 @@
+import { RPGComponentBase } from "./components/entity";
 import { evaluateConditions } from "./conditions";
+import { action, variable } from "./decorators";
 import {
     isQuest,
     type Quest,
@@ -10,8 +12,8 @@ import {
 export type QuestStatus = 'inactive' | 'active' | 'completed';
 
 export interface QuestRuntimeOptions {
-    variables: RPGVariables;
-    actions: RPGActions;
+    getVariables(): RPGVariables;
+    getActions(): RPGActions;
 }
 
 export namespace Quests {
@@ -37,16 +39,15 @@ export namespace Quests {
     }
 }
 
-export class QuestEngine {
-    private _status: QuestStatus = 'inactive';
-    private _stageIndex: number = 0;
+export class QuestEngine extends RPGComponentBase {
+    @variable('status') private _status: QuestStatus = 'inactive';
+    @variable('stage') private _stageIndex: number = 0;
 
     constructor(
         private readonly quest: Quest,
         private readonly options: QuestRuntimeOptions,
     ) {
-        this.quest = quest;
-        this.options = options;
+        super();
     }
 
     get id(): string {
@@ -54,31 +55,29 @@ export class QuestEngine {
     }
 
     isAvailable(): boolean {
-        return evaluateConditions(this.resolveConditions(this.quest.conditions ?? []), this.options.variables);
+        return evaluateConditions(this.quest.conditions ?? [], this.options.getVariables());
     }
 
+    @action
     start(): void {
         this._status = 'active';
         this._stageIndex = 0;
     }
 
-    private resolveConditions(conditions: string[]): string[] {
-        const questVar = `quest.${this.quest.id}`;
-        return conditions.map(c => c.replace(/^(~?)\$/, `$1${questVar}`));
-    }
-
+    @action
     async checkAndAdvance(): Promise<void> {
         if (this._status !== 'active') return;
 
         const stage = this.quest.stages[this._stageIndex];
         if (!stage) return;
 
-        const allDone = evaluateConditions(this.resolveConditions(stage.objectives.map(obj => obj.condition)), this.options.variables);
+        const allDone = evaluateConditions(stage.objectives.map(obj => obj.condition), this.options.getVariables());
 
         if (!allDone) return;
 
+        const actions = this.options.getActions();
         for (const action of stage.actions) {
-            await this.options.actions[action.type]?.(action.arg);
+            await actions[action.type]?.(action.arg);
         }
 
         if (this._stageIndex + 1 < this.quest.stages.length) {
@@ -88,14 +87,6 @@ export class QuestEngine {
         }
     }
 
-    getVariables(): RPGVariables {
-        const prefix = `quest.${this.quest.id}`;
-        return {
-            [prefix]: this._status,
-            [`${prefix}.stage`]: this._stageIndex,
-        };
-    }
-
     get currentStage(): QuestStage | null {
         return this.quest.stages[this._stageIndex] ?? null;
     }
@@ -105,32 +96,39 @@ export class QuestEngine {
     }
 }
 
-export class QuestManager {
+export class QuestManager extends RPGComponentBase {
     private readonly engines: Map<string, QuestEngine>;
 
     constructor(quests: Quest[], options: QuestRuntimeOptions) {
+        super();
         this.engines = new Map(quests.map(q => [q.id, new QuestEngine(q, options)]));
     }
 
+    @action
     start(questId: string): void {
         this.engines.get(questId)?.start();
     }
 
+    @action
     async checkAndAdvance(): Promise<void> {
         for (const engine of this.engines.values()) {
             await engine.checkAndAdvance();
         }
     }
 
-    getVariables(): RPGVariables {
-        const result: RPGVariables = {};
-        for (const engine of this.engines.values()) {
-            Object.assign(result, engine.getVariables());
-        }
-        return result;
-    }
-
     getEngine(questId: string): QuestEngine | undefined {
         return this.engines.get(questId);
     }
+
+    override getVariables(): RPGVariables {
+        const result: RPGVariables = {};
+        for (const [key, engine] of this.engines) {
+            for (const [varKey, value] of Object.entries(engine.getVariables())) {
+                if (value != null) {
+                    result[`${key}.${varKey}`] = value;
+                }
+            }
+        }
+        return result;
+    }
 }
diff --git a/src/common/rpg/types.ts b/src/common/rpg/types.ts
index 91f0d6a..0dfc3d9 100644
--- a/src/common/rpg/types.ts
+++ b/src/common/rpg/types.ts
@@ -1,12 +1,12 @@
 export type RPGCondition = string;
-export type RPGVariables = Record<string, string | number | boolean>;
+export type RPGVariables = Record<string, string | number | boolean | undefined>;
 
 export interface RPGAction {
     type: string;
     arg?: string | number | boolean | null;
 }
 
-export type RPGActions = Record<string, (arg?: unknown) => Promise<void> | void>;
+export type RPGActions = Record<string, (arg?: any) => unknown>;
 
 export interface DialogChoice {
     text: string;
diff --git a/src/games/playground/index.tsx b/src/games/playground/index.tsx
index 44f39cf..d32904b 100644
--- a/src/games/playground/index.tsx
+++ b/src/games/playground/index.tsx
@@ -1,10 +1,41 @@
-import { DialogEngine, Dialogs } from "@common/rpg/dialog";
-import dialogYml from './dialog.yml';
-import { isDialog } from "@common/rpg/types";
+import { RPGEntity } from "@common/rpg/components/entity";
+import { Inventory } from "@common/rpg/components/inventory";
+import { Stat } from "@common/rpg/components/stat";
+import { Variables } from "@common/rpg/components/variables";
+import { QuestManager } from "@common/rpg/quest";
+
 
 export default async function main() {
-    // console.log(dialogYml);
-    if (isDialog(dialogYml)) {
-        console.log(await Dialogs.coverageTest(dialogYml));
-    }
+    const game = new RPGEntity();
+    const player = new RPGEntity();
+    const inventory = new Inventory(['head', 'legs']);
+    const quests = new QuestManager([{
+        id: 'test',
+        description: 'Test quest',
+        title: 'Test',
+        stages: [],
+    }], game);
+    const vars = new Variables();
+
+    game.addComponent('variables', vars);
+    game.addComponent('player', player);
+    game.addComponent('quests', quests);
+    player.addComponent('inventory', inventory);
+    player.addComponent('health', new Stat(100));
+    console.log(game.getActions());
+
+    inventory.addItem({
+        itemId: 'helmet',
+        amount: 1,
+        slotId: 'head',
+    });
+    inventory.addItem({
+        itemId: 'boots',
+        amount: 2,
+    });
+    inventory.addItem({
+        itemId: 'belt',
+        amount: 1,
+    });
+    console.log(game.getVariables());
 }
\ No newline at end of file
diff --git a/src/games/zombies/tilemap.ts b/src/games/zombies/tilemap.ts
index 682b7e2..59e67b5 100644
--- a/src/games/zombies/tilemap.ts
+++ b/src/games/zombies/tilemap.ts
@@ -551,7 +551,7 @@ export default class TileMap extends Entity {
         }
     }
 
-    public update(dt: number) {
+    public override update(dt: number) {
         this.players.forEach((player) => player.update(dt));
         this.enemies.forEach((tile) => tile.enemy!.update(dt));
     }
diff --git a/tsconfig.json b/tsconfig.json
index 3309f70..d5b07cd 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -19,6 +19,7 @@
     "strict": true,
     "skipLibCheck": true,
     "noFallthroughCasesInSwitch": true,
+    "noImplicitOverride": true,
 
     // Some stricter flags (disabled by default)
     "noUnusedLocals": false,