/**** 
* Classes
****/ 
//<Assets used in the game will automatically appear here>
// 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 = 10;
	self.update = function () {
		self.x += self.speed * Math.cos(self.rotation);
		self.y += self.speed * Math.sin(self.rotation);
	};
});
// 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 () {
		var dx = player.x - self.x;
		var dy = player.y - self.y;
		var angle = Math.atan2(dy, dx);
		self.x += self.speed * Math.cos(angle);
		self.y += self.speed * Math.sin(angle);
	};
});
// Player class
var Player = Container.expand(function () {
	var self = Container.call(this);
	var playerGraphics = self.attachAsset('character', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.rotation = 0;
	self.bullets = [];
	self.shoot = function () {
		var bullet = new Bullet();
		bullet.x = self.x;
		bullet.y = self.y;
		bullet.rotation = self.rotation;
		self.bullets.push(bullet);
		game.addChild(bullet);
	};
});

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

/**** 
* Game Code
****/ 
// Initialize player
var player = new Player();
player.x = 2048 / 2;
player.y = 2732 / 2;
game.addChild(player);
// Handle mouse move to rotate player
game.move = function (x, y, obj) {
	var localPos = game.toLocal(obj.global);
	var dx = localPos.x - player.x;
	var dy = localPos.y - player.y;
	player.rotation = Math.atan2(dy, dx);
};
// Handle mouse down to shoot
var shootingInterval;
game.down = function (x, y, obj) {
	shootingInterval = LK.setInterval(function () {
		player.shoot();
	}, 100);
};
game.up = function (x, y, obj) {
	clearInterval(shootingInterval);
};
// Update game state
// Initialize enemies array
var enemies = [];
game.update = function () {
	// Create enemies at random points along the edge
	if (LK.ticks % 60 == 0) {
		var enemy = new Enemy();
		var side = Math.floor(Math.random() * 4);
		switch (side) {
			case 0:
				// top
				enemy.x = Math.random() * 2048;
				enemy.y = 0;
				break;
			case 1:
				// right
				enemy.x = 2048;
				enemy.y = Math.random() * 2732;
				break;
			case 2:
				// bottom
				enemy.x = Math.random() * 2048;
				enemy.y = 2732;
				break;
			case 3:
				// left
				enemy.x = 0;
				enemy.y = Math.random() * 2732;
				break;
		}
		enemies.push(enemy);
		game.addChild(enemy);
	}
	for (var i = player.bullets.length - 1; i >= 0; i--) {
		player.bullets[i].update();
		if (player.bullets[i].x < 0 || player.bullets[i].x > 2048 || player.bullets[i].y < 0 || player.bullets[i].y > 2732) {
			player.bullets[i].destroy();
			player.bullets.splice(i, 1);
		} else {
			for (var j = enemies.length - 1; j >= 0; j--) {
				if (player.bullets[i].intersects(enemies[j])) {
					player.bullets[i].destroy();
					player.bullets.splice(i, 1);
					enemies[j].destroy();
					enemies.splice(j, 1);
					break;
				}
			}
		}
	}
	for (var j = enemies.length - 1; j >= 0; j--) {
		if (player.intersects(enemies[j])) {
			enemies[j].destroy();
			enemies.splice(j, 1);
		}
	}
};

===================================================================
--- original.js
+++ change.js
@@ -74,9 +74,9 @@
 };
 // Handle mouse down to shoot
 var shootingInterval;
 game.down = function (x, y, obj) {
-	shootingInterval = setInterval(function () {
+	shootingInterval = LK.setInterval(function () {
 		player.shoot();
 	}, 100);
 };
 game.up = function (x, y, obj) {