/**** 
* Classes
****/ 
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.x += self.speed;
		if (self.x < 0) {
			self.destroy();
		}
	};
});
var Enemy = Container.expand(function () {
	var self = Container.call(this);
	var enemyGraphics = self.attachAsset('enemy', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = -3;
	self.update = function () {
		self.x += self.speed;
		if (self.x < 0 || self.x > 2048) {
			self.destroy();
		}
	};
});
var Ground = Container.expand(function () {
	var self = Container.call(this);
	var groundGraphics = self.attachAsset('ground', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.update = function () {
		// Ground does not move
	};
});
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 () {
		if (self.x < 0) {
			self.x = 0;
		}
		if (self.x > 2048) {
			self.x = 2048;
		}
		// Player only moves horizontally
	};
});

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

/**** 
* Game Code
****/ 
var ground = game.addChild(new Ground());
ground.x = 1024;
ground.y = 2732 - 50;
var player = game.addChild(new Player());
player.x = 1024;
player.y = ground.y - 150;
var enemies = [];
var bullets = [];
game.update = function () {
	if (LK.ticks % Math.floor(Math.random() * 100) == 0) {
		var enemy = game.addChild(new Enemy());
		enemy.x = 2048;
		enemy.y = ground.y - 150;
		enemies.push(enemy);
	}
	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);
				break;
			}
		}
	}
};
game.down = function (x, y, obj) {
	var bullet = game.addChild(new Bullet());
	bullet.x = player.x;
	bullet.y = player.y;
	bullets.push(bullet);
};
game.move = function (x, y, obj) {
	player.x = x;
	// Player only moves horizontally
};

===================================================================
--- original.js
+++ change.js
@@ -75,9 +75,9 @@
 player.y = ground.y - 150;
 var enemies = [];
 var bullets = [];
 game.update = function () {
-	if (LK.ticks % Math.floor(Math.random() * 60) == 0) {
+	if (LK.ticks % Math.floor(Math.random() * 100) == 0) {
 		var enemy = game.addChild(new Enemy());
 		enemy.x = 2048;
 		enemy.y = ground.y - 150;
 		enemies.push(enemy);