/**** 
* Classes
****/ 
// Bullet class
var Bullet = Container.expand(function () {
	var self = Container.call(this);
	var bulletGraphics = self.attachAsset('bullet', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = -5;
	self.update = function () {
		self.y += self.speed;
	};
});
// Car class
var Car = Container.expand(function () {
	var self = Container.call(this);
	var carGraphics = self.attachAsset('car', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = 5;
	self.update = function () {
		self.y += self.speed;
	};
});
// Enemy class
var Enemy = Container.expand(function () {
	var self = Container.call(this);
	var enemyGraphics = self.attachAsset('enemy', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = 2;
	self.update = function () {
		self.y += self.speed;
	};
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x000000 //Init game with black background
});

/**** 
* Game Code
****/ 
// Initialize the car
var car = game.addChild(new Car());
car.x = 2048 / 2;
car.y = 2732 - 100;
// Initialize the bullets
var bullets = [];
// Initialize the enemies
var enemies = [];
for (var i = 0; i < 10; i++) {
	var enemy = game.addChild(new Enemy());
	enemy.x = Math.random() * 2048;
	enemy.y = Math.random() * 500;
	enemies.push(enemy);
}
// Initialize LK.keys object
LK.keys = {
	'ArrowLeft': false,
	'ArrowRight': false,
	'Space': false
};
game.update = function () {
	// Move the car
	if (LK.keys['ArrowLeft']) {
		car.x -= car.speed;
	}
	if (LK.keys['ArrowRight']) {
		car.x += car.speed;
	}
	// Shoot bullets
	if (LK.keys['Space']) {
		var bullet = game.addChild(new Bullet());
		bullet.x = car.x;
		bullet.y = car.y;
		bullets.push(bullet);
		LK.getSound('shoot').play();
	}
	// Check for collisions
	for (var i = bullets.length - 1; i >= 0; i--) {
		var bullet = bullets[i];
		for (var j = enemies.length - 1; j >= 0; j--) {
			var enemy = enemies[j];
			if (bullet.intersects(enemy)) {
				bullet.destroy();
				bullets.splice(i, 1);
				enemy.destroy();
				enemies.splice(j, 1);
				LK.getSound('enemyDestroyed').play();
				break;
			}
		}
	}
};

===================================================================
--- original.js
+++ change.js
@@ -61,8 +61,14 @@
 	enemy.x = Math.random() * 2048;
 	enemy.y = Math.random() * 500;
 	enemies.push(enemy);
 }
+// Initialize LK.keys object
+LK.keys = {
+	'ArrowLeft': false,
+	'ArrowRight': false,
+	'Space': false
+};
 game.update = function () {
 	// Move the car
 	if (LK.keys['ArrowLeft']) {
 		car.x -= car.speed;