/**** 
* Classes
****/ 
// Define a class for bullets
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.y += self.speed;
		// Destroy the bullet if it goes off the screen
		if (self.y < 0 || self.y > 2732) {
			self.destroy();
		}
	};
});
// Define a class for enemies
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;
		if (self.y > 2732) {
			self.y = 0;
			self.x = Math.random() * 2048;
		}
	};
});
//<Assets used in the game will automatically appear here>
//<Write imports for supported plugins here>
// Define a class for the player character
var Player = Container.expand(function () {
	var self = Container.call(this);
	var playerGraphics = self.attachAsset('player', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = 5;
	self.update = function () {
		// Update logic for player
	};
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x008000 //Init game with green background
});

/**** 
* Game Code
****/ 
// Initialize player
var player = game.addChild(new Player());
player.x = 1024;
player.y = 2500;
// Initialize enemies
var enemies = [];
for (var i = 0; i < 5; i++) {
	var enemy = new Enemy();
	enemy.x = Math.random() * 2048;
	enemy.y = Math.random() * 1000;
	enemies.push(enemy);
	game.addChild(enemy);
}
// Initialize bullets
var bullets = [];
// Handle player movement
game.move = function (x, y, obj) {
	player.x = x;
	player.y = y;
};
// Handle shooting
game.down = function (x, y, obj) {
	var bullet = new Bullet();
	bullet.x = player.x;
	bullet.y = player.y;
	bullets.push(bullet);
	game.addChild(bullet);
};
// Update game state
game.update = function () {
	// Update enemies
	for (var i = 0; i < enemies.length; i++) {
		enemies[i].update();
	}
	// Update bullets
	for (var j = bullets.length - 1; j >= 0; j--) {
		bullets[j].update();
		if (bullets[j].y < 0) {
			bullets.splice(j, 1);
		}
	}
	// Check for collisions
	for (var k = bullets.length - 1; k >= 0; k--) {
		for (var l = enemies.length - 1; l >= 0; l--) {
			if (bullets[k].intersects(enemies[l])) {
				bullets[k].destroy();
				enemies[l].destroy();
				bullets.splice(k, 1);
				enemies.splice(l, 1);
				break;
			}
		}
	}
};

===================================================================
--- original.js
+++ change.js
@@ -51,9 +51,9 @@
 /**** 
 * Initialize Game
 ****/ 
 var game = new LK.Game({
-	backgroundColor: 0x000000 //Init game with black background 
+	backgroundColor: 0x008000 //Init game with green background
 });
 
 /**** 
 * Game Code