diff --git a/packages/demos/game-playground/src/index.ts b/packages/demos/game-playground/src/index.ts
index 33cd9f4..d7853a1 100644
--- a/packages/demos/game-playground/src/index.ts
+++ b/packages/demos/game-playground/src/index.ts
@@ -25,7 +25,7 @@ import AttackingWithClubSystem from "./system/AttackingWithClubSystem";
 import MatrixSystem from "./system/MatrixSystem";
 import { createHtmlUiElements, PreRenderTiledMapSystem } from "@serbanghita-gamedev/renderer";
 
-async function runGame() {
+async function setup() {
   // 0. Create the UI and canvas.
   const [, CANVAS_BACKGROUND, CANVAS_FOREGROUND] = createHtmlUiElements();
 
@@ -106,4 +106,4 @@ async function runGame() {
   };
 }
 
-runGame().then(() => console.log("Game started ..."));
+setup().then(() => console.log("Game started ..."));
diff --git a/packages/demos/game-playground/src/system/RenderSystem.ts b/packages/demos/game-playground/src/system/RenderSystem.ts
index d942061..e252a19 100644
--- a/packages/demos/game-playground/src/system/RenderSystem.ts
+++ b/packages/demos/game-playground/src/system/RenderSystem.ts
@@ -1,5 +1,5 @@
 import { System, Query, World } from "@serbanghita-gamedev/ecs";
-import { clearCtx, getCtx, renderImage, renderRectangle } from "@serbanghita-gamedev/renderer";
+import { clearCtx, getCtx, image, rectangle } from "@serbanghita-gamedev/renderer";
 import { Position, SpriteSheet } from "@serbanghita-gamedev/component";
 import IsWalking from "../component/IsWalking";
 import IsIdle from "../component/IsIdle";
@@ -66,7 +66,7 @@ export default class RenderSystem extends System {
         );
       }
 
-      renderImage(
+      image(
         getCtx(this.CANVAS),
         spriteSheetImg,
         // source
@@ -81,7 +81,7 @@ export default class RenderSystem extends System {
         animationFrame.height,
       );
 
-      renderRectangle(
+      rectangle(
         getCtx(this.CANVAS) as CanvasRenderingContext2D,
         destPositionX,
         destPositionY,
@@ -90,7 +90,7 @@ export default class RenderSystem extends System {
         "#cccccc",
       );
 
-      renderRectangle(
+      rectangle(
         getCtx(this.CANVAS) as CanvasRenderingContext2D,
         destPositionX + hitboxOffset.x,
         destPositionY + hitboxOffset.y,
diff --git a/packages/demos/tiled-rendering/src/IsCollisionTile.ts b/packages/demos/tiled-rendering/src/IsCollisionTile.ts
new file mode 100644
index 0000000..ce007e4
--- /dev/null
+++ b/packages/demos/tiled-rendering/src/IsCollisionTile.ts
@@ -0,0 +1,16 @@
+import { Component } from "@serbanghita-gamedev/ecs";
+import { Point } from "@serbanghita-gamedev/geometry";
+
+export interface IsCollisionTileProps {
+  x: number;
+  y: number;
+  point: Point;
+  // Tile index.
+  tile: number;
+}
+
+export default class IsCollisionTile extends Component {
+  constructor(public properties: IsCollisionTileProps) {
+    super(properties);
+  }
+}
diff --git a/packages/demos/tiled-rendering/src/IsMatrix.ts b/packages/demos/tiled-rendering/src/IsMatrix.ts
new file mode 100644
index 0000000..22ae762
--- /dev/null
+++ b/packages/demos/tiled-rendering/src/IsMatrix.ts
@@ -0,0 +1,18 @@
+import { Component } from "@serbanghita-gamedev/ecs";
+
+export interface IsMatrixProps {
+  // Flat array matrix with all the possible entities, obstacles, etc.
+  matrix: number[];
+  // Width in tiles.
+  width: number;
+  // Height in tiles.
+  height: number;
+  // Size of the tile in pixels.
+  tileSize: number;
+}
+
+export default class IsMatrix extends Component {
+  constructor(public properties: IsMatrixProps) {
+    super(properties);
+  }
+}
diff --git a/packages/demos/tiled-rendering/src/IsPlayer.ts b/packages/demos/tiled-rendering/src/IsPlayer.ts
new file mode 100644
index 0000000..20c27e6
--- /dev/null
+++ b/packages/demos/tiled-rendering/src/IsPlayer.ts
@@ -0,0 +1,7 @@
+import { Component } from "@serbanghita-gamedev/ecs";
+
+export default class IsPlayer extends Component {
+  constructor(public properties: Record<string, never>) {
+    super(properties);
+  }
+}
diff --git a/packages/demos/tiled-rendering/src/IsPreRendered.ts b/packages/demos/tiled-rendering/src/IsPreRendered.ts
new file mode 100644
index 0000000..8d9f924
--- /dev/null
+++ b/packages/demos/tiled-rendering/src/IsPreRendered.ts
@@ -0,0 +1,7 @@
+import { Component } from "@serbanghita-gamedev/ecs";
+
+export default class IsPreRendered extends Component {
+  constructor(public properties: Record<string, never>) {
+    super(properties);
+  }
+}
diff --git a/packages/demos/tiled-rendering/src/IsRenderedInForeground.ts b/packages/demos/tiled-rendering/src/IsRenderedInForeground.ts
new file mode 100644
index 0000000..39d1e28
--- /dev/null
+++ b/packages/demos/tiled-rendering/src/IsRenderedInForeground.ts
@@ -0,0 +1,7 @@
+import { Component } from "@serbanghita-gamedev/ecs";
+
+export default class IsRenderedInForeground extends Component {
+  constructor(public properties: Record<string, never>) {
+    super(properties);
+  }
+}
diff --git a/packages/demos/tiled-rendering/src/MoveSystem.ts b/packages/demos/tiled-rendering/src/MoveSystem.ts
new file mode 100644
index 0000000..baaa483
--- /dev/null
+++ b/packages/demos/tiled-rendering/src/MoveSystem.ts
@@ -0,0 +1,41 @@
+import { System, Query, World, Entity } from "@serbanghita-gamedev/ecs";
+import { QuadTree } from "@serbanghita-gamedev/quadtree";
+import PhysicsBody from "./PhysicsBody";
+import { randomInt } from "./helpers";
+import IsCollisionTile from "./IsCollisionTile";
+import IsMatrix from "./IsMatrix";
+import { getTileFromCoordinates } from "@serbanghita-gamedev/matrix";
+
+export default class MoveSystem extends System {
+  public constructor(
+    public world: World,
+    public query: Query,
+  ) {
+    super(world, query);
+  }
+
+  public update(now) {
+    const map = this.world.getEntity("map");
+    if (!map) {
+      throw new Error(`Map entity is not defined.`);
+    }
+    const matrixComponent = map.getComponent(IsMatrix);
+    const matrix = matrixComponent.properties.matrix;
+
+    this.query.execute().forEach((entity) => {
+      const tile = entity.getComponent(IsCollisionTile);
+
+      let futureX = tile.properties.x + randomInt(-1, 1);
+      let futureY = tile.properties.y + randomInt(-1, 1);
+
+      const futureTile = getTileFromCoordinates(futureX, futureY, matrixComponent.properties);
+      if (matrix[futureTile] === 0) {
+        tile.properties.x = futureX;
+        tile.properties.y = futureY;
+        tile.properties.point.x = futureX;
+        tile.properties.point.y = futureY;
+        tile.properties.tile = futureTile;
+      }
+    });
+  }
+}
diff --git a/packages/demos/tiled-rendering/src/PhysicsBody.ts b/packages/demos/tiled-rendering/src/PhysicsBody.ts
new file mode 100644
index 0000000..e498e7d
--- /dev/null
+++ b/packages/demos/tiled-rendering/src/PhysicsBody.ts
@@ -0,0 +1,17 @@
+import { Component } from "@serbanghita-gamedev/ecs";
+import { Rectangle, Point } from "@serbanghita-gamedev/geometry";
+
+export interface PhysicsBodyProps {
+  width: number;
+  height: number;
+  x: number;
+  y: number;
+  rectangle: Rectangle;
+  point: Point;
+}
+
+export default class PhysicsBody extends Component {
+  constructor(public properties: PhysicsBodyProps) {
+    super(properties);
+  }
+}
diff --git a/packages/demos/tiled-rendering/src/PreRenderCollisionTilesSystem.ts b/packages/demos/tiled-rendering/src/PreRenderCollisionTilesSystem.ts
new file mode 100644
index 0000000..e0b1fe4
--- /dev/null
+++ b/packages/demos/tiled-rendering/src/PreRenderCollisionTilesSystem.ts
@@ -0,0 +1,21 @@
+import { System, Query, World, Entity } from "@serbanghita-gamedev/ecs";
+import IsCollisionTile from "./IsCollisionTile";
+import { dot } from "@serbanghita-gamedev/renderer";
+
+export default class PreRenderCollisionTilesSystem extends System {
+  public constructor(
+    public world: World,
+    public query: Query,
+    public ctx: CanvasRenderingContext2D,
+  ) {
+    super(world, query);
+  }
+
+  public update(now: number): void {
+    this.query.execute().forEach((entity) => {
+      const tile = entity.getComponent(IsCollisionTile);
+      const point = tile.properties.point;
+      dot(this.ctx, point.x, point.y, "rgb(255,0,0)", 2);
+    });
+  }
+}
diff --git a/packages/demos/tiled-rendering/src/QuadTreeSystem.ts b/packages/demos/tiled-rendering/src/QuadTreeSystem.ts
new file mode 100644
index 0000000..2b52669
--- /dev/null
+++ b/packages/demos/tiled-rendering/src/QuadTreeSystem.ts
@@ -0,0 +1,27 @@
+import { System, Query, World } from "@serbanghita-gamedev/ecs";
+import { QuadTree } from "@serbanghita-gamedev/quadtree";
+import IsCollisionTile from "./IsCollisionTile";
+
+export default class QuadTreeSystem extends System {
+  public constructor(
+    public world: World,
+    public query: Query,
+    public quadtree: QuadTree,
+  ) {
+    super(world, query);
+  }
+  public update(now: number): void {
+    this.preUpdate();
+
+    if (this.isPaused) {
+      return;
+    }
+
+    this.quadtree.clear();
+
+    this.query.execute().forEach((entity) => {
+      const tile = entity.getComponent(IsCollisionTile);
+      this.quadtree.addPoint(tile.properties.point);
+    });
+  }
+}
diff --git a/packages/demos/tiled-rendering/src/RenderingSystem.ts b/packages/demos/tiled-rendering/src/RenderingSystem.ts
new file mode 100644
index 0000000..29526d8
--- /dev/null
+++ b/packages/demos/tiled-rendering/src/RenderingSystem.ts
@@ -0,0 +1,36 @@
+import { System, Query, World, Entity } from "@serbanghita-gamedev/ecs";
+import IsCollisionTile from "./IsCollisionTile";
+import { dot, rectangle, text } from "@serbanghita-gamedev/renderer";
+import { QuadTree } from "@serbanghita-gamedev/quadtree";
+
+export default class RenderingSystem extends System {
+  public constructor(
+    public world: World,
+    public query: Query,
+    public ctx: CanvasRenderingContext2D,
+    public quadtree: QuadTree,
+  ) {
+    super(world, query);
+  }
+
+  private renderQuadTree(quadtree: QuadTree) {
+    rectangle(this.ctx, quadtree.area.topLeftX, quadtree.area.topLeftY, quadtree.area.width, quadtree.area.height, "rgba(0,0,0,0.5)");
+
+    Object.values(quadtree.quadrants).forEach((subQuadtree) => {
+      this.renderQuadTree(subQuadtree);
+    });
+  }
+
+  public update(now: number): void {
+    this.ctx.clearRect(0, 0, 640, 480);
+
+    this.query.execute().forEach((entity) => {
+      const tile = entity.getComponent(IsCollisionTile);
+      const point = tile.properties.point;
+      dot(this.ctx, point.x, point.y, "rgb(0,255,0)", 6);
+      text(this.ctx, `${tile.properties.tile}`, point.x, point.y, "10", "arial", "", "black");
+    });
+
+    this.renderQuadTree(this.quadtree);
+  }
+}
diff --git a/packages/demos/tiled-rendering/src/helpers.ts b/packages/demos/tiled-rendering/src/helpers.ts
new file mode 100644
index 0000000..e42869f
--- /dev/null
+++ b/packages/demos/tiled-rendering/src/helpers.ts
@@ -0,0 +1,3 @@
+export function randomInt(min: number, max: number): number {
+  return Math.floor(Math.random() * (max - min + 1)) + min;
+}
\ No newline at end of file
diff --git a/packages/demos/tiled-rendering/src/index.ts b/packages/demos/tiled-rendering/src/index.ts
index 39f734d..30b5db9 100644
--- a/packages/demos/tiled-rendering/src/index.ts
+++ b/packages/demos/tiled-rendering/src/index.ts
@@ -1,20 +1,30 @@
 // 0. Create the UI and canvas.
-import { createWrapperElement, createCanvas, run, dot } from "@serbanghita-gamedev/renderer";
+import { createWrapperElement, createCanvas, run, dot, rectangle } from "@serbanghita-gamedev/renderer";
 import { World } from "@serbanghita-gamedev/ecs";
 import { PreRenderTiledMapSystem } from "@serbanghita-gamedev/renderer";
-import { IsTiledMap } from "@serbanghita-gamedev/component";
+import { IsTiledMap, Renderable } from "@serbanghita-gamedev/component";
 import { loadSprites } from "./assets";
-import { Point } from "@serbanghita-gamedev/geometry";
-
-export function randomInt(min: number, max: number): number {
-  return Math.floor(Math.random() * (max - min + 1)) + min;
-}
+import { Point, Rectangle } from "@serbanghita-gamedev/geometry";
+import { randomInt } from "./helpers";
+import IsMatrix from "./IsMatrix";
+import { TiledMap } from "@serbanghita-gamedev/tiled";
+import { getTileCoordinates } from "@serbanghita-gamedev/matrix";
+import { QuadTree } from "@serbanghita-gamedev/quadtree";
+import QuadTreeSystem from "./QuadTreeSystem";
+import IsCollisionTile from "./IsCollisionTile";
+import IsPreRendered from "./IsPreRendered";
+import PreRenderCollisionTilesSystem from "./PreRenderCollisionTilesSystem";
+import IsRenderedInForeground from "./IsRenderedInForeground";
+import RenderingSystem from "./RenderingSystem";
+import IsPlayer from "./IsPlayer";
+import MoveSystem from "./MoveSystem";
 
 async function setup() {
   const HTML_WRAPPER = createWrapperElement("game-wrapper", 640, 480);
   const CANVAS_FOREGROUND = createCanvas("foreground", 640, 480, "2");
   const CTX_FOREGROUND = CANVAS_FOREGROUND.getContext("2d") as CanvasRenderingContext2D;
   const CANVAS_BACKGROUND = createCanvas("background", 640, 480, "1");
+  const CTX_BACKGROUND = CANVAS_BACKGROUND.getContext("2d") as CanvasRenderingContext2D;
   HTML_WRAPPER.appendChild(CANVAS_FOREGROUND);
   HTML_WRAPPER.appendChild(CANVAS_BACKGROUND);
   document.body.appendChild(HTML_WRAPPER);
@@ -24,25 +34,66 @@ async function setup() {
   // Create the current "World" (scene).
   const world = new World();
 
-  world.declarations.components.registerComponent(IsTiledMap);
+  world.registerComponent(IsTiledMap);
+  world.registerComponent(IsMatrix);
+  world.registerComponent(IsCollisionTile);
+  world.registerComponent(IsPreRendered);
+  world.registerComponent(IsRenderedInForeground);
+  world.registerComponent(IsPlayer);
 
-  const CustomMapEntity = world.createEntity("map");
-  CustomMapEntity.addComponent(IsTiledMap, { mapFile: require("./assets/maps/E1MM2.json"), mapFilePath: "./assets/maps/E1MM2.json" });
+  // Load the map from Tiled json file declaration.
+  // Create a dedicated map entity.
+  const map = world.createEntity("map");
+  map.addComponent(IsTiledMap, { mapFile: require("./assets/maps/E1MM2.json"), mapFilePath: "./assets/maps/E1MM2.json" });
+  // Load the "TiledMap" class wrapper over the json file declaration.
+  const tiledMap = new TiledMap(map.getComponent(IsTiledMap).properties.mapFile);
+  // Add the "collision" layer data to the map.
+  const collisionLayer = tiledMap.getCollisionLayers()[0];
+  map.addComponent(IsMatrix, { matrix: collisionLayer.data, width: collisionLayer.width, height: collisionLayer.height, tileSize: 16 });
+
+  // Transform all collision tiles as entities.
+  collisionLayer.data.forEach((tileValue, tileIndex) => {
+    if (tileValue > 0) {
+      const entityId = `collision-tile-${tileIndex}`;
+      const collisionTileEntity = world.createEntity(entityId);
+      let { x, y } = getTileCoordinates(tileIndex, map.getComponent(IsMatrix).properties);
+      x = x + 16 / 2;
+      y = y + 16 / 2;
+      collisionTileEntity.addComponent(IsCollisionTile, { x, y, point: new Point(x, y, entityId) });
+      collisionTileEntity.addComponent(IsPreRendered);
+    }
+  });
 
   const TiledMapQuery = world.createQuery("TiledMapQuery", { all: [IsTiledMap] });
   world.createSystem(PreRenderTiledMapSystem, TiledMapQuery, CANVAS_BACKGROUND, SPRITES["./assets/sprites/terrain.png"]).runOnlyOnce();
 
-  const point = new Point(640 / 2, 480 / 2);
+  // Quadtree
+  const area = new Rectangle(640, 480, new Point(640 / 2, 480 / 2));
+  const quadtree = new QuadTree(area, 5, 5);
 
-  world.start(() => {
-      CTX_FOREGROUND.clearRect(0, 0, 640, 480);
-      // No need to re-render the "background" layer if it's static.
-      // image(CTX_FOREGROUND, CANVAS_BACKGROUND, 0, 0, 640, 480, 0, 0, 640, 480);
+  const CollisionTilesQuery = world.createQuery("CollisionTilesQuery", { all: [IsCollisionTile] });
+  world.createSystem(PreRenderCollisionTilesSystem, CollisionTilesQuery, CTX_BACKGROUND).runOnlyOnce();
 
-      point.x += randomInt(-2, 2);
-      point.y += randomInt(-2, 2);
-      dot(CTX_FOREGROUND, point.x, point.y, "rgb(255,0,0)", 10);
+  const RenderingQuery = world.createQuery("RenderingQuery", { all: [IsRenderedInForeground] });
+  world.createSystem(RenderingSystem, RenderingQuery, CTX_FOREGROUND, quadtree);
+  const IsPlayerQuery = world.createQuery("IsPlayerQuery", { all: [IsPlayer] });
+  world.createSystem(MoveSystem, IsPlayerQuery);
+  world.createSystem(QuadTreeSystem, IsPlayerQuery, quadtree);
+
+  CANVAS_FOREGROUND.addEventListener("dblclick", (event) => {
+    const x = event.clientX | 0;
+    const y = event.clientY | 0;
+
+    const playerId = `player-${x}-${y}`;
+    const player = world.createEntity(playerId);
+    const point = new Point(x, y, playerId);
+    player.addComponent(IsCollisionTile, { x, y, point });
+    player.addComponent(IsRenderedInForeground);
+    player.addComponent(IsPlayer);
+    quadtree.addPoint(point);
   });
+
+  world.start(0, () => {});
 }
 
 setup().then(() => console.log("Game started ..."));
diff --git a/packages/ecs/src/Query.ts b/packages/ecs/src/Query.ts
index bb0389d..e2b6ea6 100644
--- a/packages/ecs/src/Query.ts
+++ b/packages/ecs/src/Query.ts
@@ -32,9 +32,21 @@ export default class Query {
      * @param filters
      */
     constructor(public world: World, public id: string, public filters: IQueryFilters) {
+        this.checkIfComponentsAreRegistered();
         this.processFiltersAsBitMasks();
     }
 
+    private checkIfComponentsAreRegistered() {
+      // Get a list of unique "Components" that are being used in the filters.
+      [...new Set<typeof Component>(Object.values(this.filters).reduce((acc, value) => {
+        return acc.concat(value);
+      }, []))].forEach((component) => {
+        if (typeof component.prototype.bitmask === "undefined") {
+          throw new Error(`Please register the component ${component.name} in the ComponentRegistry.`);
+        }
+      });
+    }
+
     private processFiltersAsBitMasks(): void {
         if (this.filters.all) {
             this.filters.all.forEach((component) => {
diff --git a/packages/ecs/src/World.ts b/packages/ecs/src/World.ts
index 0deb638..7efdd24 100644
--- a/packages/ecs/src/World.ts
+++ b/packages/ecs/src/World.ts
@@ -15,6 +15,11 @@ export default class World {
   public systems = new Map<typeof System, System>();
   public fps: number = 0;
 
+  public registerComponent(declaration: typeof Component)
+  {
+    this.declarations.components.registerComponent(declaration);
+  }
+
   public createQuery(id: string, filters: IQueryFilters): Query {
     const query = new Query(this, id, filters);
 
diff --git a/packages/renderer/src/canvas.ts b/packages/renderer/src/canvas.ts
index 2351d27..939fd9d 100644
--- a/packages/renderer/src/canvas.ts
+++ b/packages/renderer/src/canvas.ts
@@ -35,8 +35,8 @@ export function text(
   y: number,
   fontSize: string = "10",
   fontFamily: string = "arial",
-  strokeColor?: string,
-  fillColor?: string,
+  strokeColor: string = 'black',
+  fillColor: string = 'black',
 ) {
   ctx.save();
   ctx.font = `${fontSize}px ${fontFamily}`;
@@ -121,10 +121,10 @@ export function renderTile(
 }
 
 export function dot(ctx: CanvasRenderingContext2D, x: number, y: number, fillColor: string = "rgb(0,0,0)", size: number = 1) {
-  // ctx.save();
+  ctx.save();
   ctx.fillStyle = fillColor;
   ctx.fillRect(x, y, size, size);
-  // ctx.restore();
+  ctx.restore();
 }
 
 export function rectangle(ctx: CanvasRenderingContext2D, x: number, y: number, width: number, height: number, strokeColor: string = "black", fillColor?: string): void {