var Base = Container.expand(function () {
	var self = Container.call(this);
	var baseGraphics = self.createAsset('base', 'Base Graphics', .5, .5);
	self.health = 100;
	self.updateHealth = function () {};
});
var Enemy = Container.expand(function () {
	var self = Container.call(this);
	var enemyGraphics = self.createAsset('enemy', 'Enemy Graphics', .5, .5);
	self.speed = 1;
	self.move = function () {
		self.y += self.speed;
	};
	self.attack = function () {};
});
var HeroBullet = Container.expand(function () {
	var self = Container.call(this);
	var bulletGraphics = self.createAsset('bullet', 'Bullet Graphics', .5, .5);
	self.speed = 5;
	self.move = function () {};
});
var Spawner = Container.expand(function (x, y) {
	var self = Container.call(this);
	var spawnerGraphics = self.createAsset('spawner', 'Spawner Graphics', .5, .5);
	self.x = x;
	self.y = y;
	self.spawnEnemy = function () {
		var enemy = new Enemy();
		enemy.x = self.x;
		enemy.y = self.y;
		self.parent.enemies.push(enemy);
		self.parent.addChild(enemy);
	};
});
var Game = Container.expand(function () {
	var self = Container.call(this);
	self.enemies = [];
	var base = self.addChild(new Base());
	var bullets = [];
	base.x = 2048 / 2;
	base.y = 2732 - base.height / 2;
	var spawner1 = self.addChild(new Spawner(2048 / 6, 200));
	var spawner2 = self.addChild(new Spawner(2048 / 2, 200));
	var spawner3 = self.addChild(new Spawner(2048 / 6 * 5, 200));
	var spawner1Timer = LK.setInterval(function () {
		spawner1.spawnEnemy();
	}, 3000);
	var spawner2Timer = LK.setInterval(function () {
		spawner2.spawnEnemy();
	}, 3000);
	var spawner3Timer = LK.setInterval(function () {
		spawner3.spawnEnemy();
	}, 3000);
	var fireBullet = function (x, y) {
		var bullet = new HeroBullet();
		bullet.x = x;
		bullet.y = y;
		bullets.push(bullet);
		self.addChild(bullet);
	};
	self.on('down', function (obj) {
		var pos = obj.event.getLocalPosition(self);
		fireBullet(pos.x, pos.y);
	});
	LK.on('tick', function () {
		for (var i = 0; i < enemies.length; i++) {
			enemies[i].move();
			if (enemies[i].intersects(base)) {
				enemies[i].attack();
				enemies[i].destroy();
				enemies.splice(i, 1);
				i--;
			}
		}
		for (var i = 0; i < bullets.length; i++) {
			bullets[i].move();
			for (var j = 0; j < enemies.length; j++) {
				if (bullets[i].intersects(enemies[j])) {
					bullets[i].destroy();
					bullets.splice(i, 1);
					i--;
					enemies[j].destroy();
					enemies.splice(j, 1);
					break;
				}
			}
		}
		if (base.health <= 0) {
			LK.showGameOver();
		}
	});
});

===================================================================
--- original.js
+++ change.js
@@ -27,16 +27,16 @@
 	self.spawnEnemy = function () {
 		var enemy = new Enemy();
 		enemy.x = self.x;
 		enemy.y = self.y;
-		enemies.push(enemy);
+		self.parent.enemies.push(enemy);
 		self.parent.addChild(enemy);
 	};
 });
 var Game = Container.expand(function () {
 	var self = Container.call(this);
+	self.enemies = [];
 	var base = self.addChild(new Base());
-	var enemies = [];
 	var bullets = [];
 	base.x = 2048 / 2;
 	base.y = 2732 - base.height / 2;
 	var spawner1 = self.addChild(new Spawner(2048 / 6, 200));