var Shuriken = Container.expand(function () {
	var self = Container.call(this);
	var shurikenGraphics = self.createAsset('shuriken', 'Shuriken Graphics', .5, .5);
	self.speed = 5;
	self.move = function () {
		;
		self.y += self.speed;
	};
	self.destroy = function () {};
});
var Rat = Container.expand(function () {
	var self = Container.call(this);
	var ratGraphics = self.createAsset('rat', 'Rat Graphics', .5, .5);
	self.speed = 2;
	self.move = function () {
		self.y += self.speed;
	};
	self.destroy = function () {};
});
var PowerUp = Container.expand(function () {
	var self = Container.call(this);
	var powerUpGraphics = self.createAsset('powerUp', 'PowerUp Graphics', .5, .5);
	self.activate = function () {};
});
var Game = Container.expand(function () {
	var self = Container.call(this);
	var background = self.createAsset('wooden_floor', 'Level Background', 0, 0);
	background.width = 2048;
	background.height = 2732;
	background.isCollisionObject = false;
	var scoreTxt = new Text2('0', {
		size: 150,
		fill: "#ffffff"
	});
	scoreTxt.anchor.set(.5, 0);
	LK.gui.topCenter.addChild(scoreTxt);
	var shurikens = [];
	var rats = [];
	var powerUps = [];
	var isGameOver = false;
	var tickOffset = 0;
	var score = 0;
	function init() {
		spawnRats();
	}
	function spawnRats() {
		var spawnTime = Math.random() * 2000 + 1000;
		LK.setTimeout(function () {
			var rat = new Rat();
			rat.x = Math.random() * 2048;
			rat.y = 0;
			rats.push(rat);
			self.addChild(rat);
			spawnRats();
		}, spawnTime);
	}
	function update() {}
	function gameOver() {}
	function checkCollision() {}
	function updateScore() {}
	stage.on('down', function (obj) {});
	stage.on('move', function (obj) {});
	stage.on('up', function (obj) {});
	LK.on('tick', function () {
		update();
		for (var i = 0; i < rats.length; i++) {
			rats[i].move();
		}
		checkCollision();
		updateScore();
		if (isGameOver) {
			gameOver();
		}
	});
	init();
});

===================================================================
--- original.js
+++ change.js
@@ -62,8 +62,11 @@
 	stage.on('move', function (obj) {});
 	stage.on('up', function (obj) {});
 	LK.on('tick', function () {
 		update();
+		for (var i = 0; i < rats.length; i++) {
+			rats[i].move();
+		}
 		checkCollision();
 		updateScore();
 		if (isGameOver) {
 			gameOver();