/**** 
* Classes
****/ 
var Enemy1 = Container.expand(function () {
	var self = Container.call(this);
	var enemyGraphics = self.attachAsset('enemy1', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = 3;
	self._move_migrated = function () {
		self.y += self.speed;
	};
});
var Enemy2 = Container.expand(function () {
	var self = Container.call(this);
	var enemyGraphics = self.attachAsset('enemy2', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = 2;
	self._move_migrated = function () {
		self.y += self.speed;
	};
});
var Enemy3 = Container.expand(function () {
	var self = Container.call(this);
	var enemyGraphics = self.attachAsset('enemy3', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = 4;
	self._move_migrated = function () {
		self.y += self.speed;
	};
});
var Enemy4 = Container.expand(function () {
	var self = Container.call(this);
	var enemyGraphics = self.attachAsset('enemy4', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = 5;
	self._move_migrated = function () {
		self.y += self.speed;
	};
});
var EnemyBullet = Container.expand(function () {
	var self = Container.call(this);
	var bulletGraphics = self.attachAsset('enemyBullet', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = 10;
	self._move_migrated = function () {
		self.y += self.speed;
		if (self.y > 2732) {
			self.destroy();
		}
	};
});
var HealthDisplay = Container.expand(function () {
	var self = Container.call(this);
	self.healthCircles = [];
	for (var i = 0; i < 3; i++) {
		var healthCircle = self.attachAsset('healthCircle', {});
		healthCircle.x = i * 100;
		self.healthCircles.push(healthCircle);
		self.addChild(healthCircle);
	}
	self.updateHealth = function (health) {
		for (var i = 0; i < self.healthCircles.length; i++) {
			self.healthCircles[i].alpha = i < health ? 1 : 0.5;
		}
	};
});
var Hero = Container.expand(function () {
	var self = Container.call(this);
	self.health = 3;
	var heroGraphics = self.attachAsset('hero', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = 5;
	self.bulletSpeed = 10;
	self.lastBulletTime = 0;
	self._move_migrated = function () {};
	self.fire = function () {
		var bullet = new HeroBullet();
		bullet.x = self.x;
		bullet.y = self.y;
		bullet.speed = self.bulletSpeed;
		heroBullets.push(bullet);
		self.parent.addChild(bullet);
	};
});
var HeroBullet = Container.expand(function () {
	var self = Container.call(this);
	var bulletGraphics = self.attachAsset('heroBullet', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = 10;
	self._move_migrated = function () {
		self.y += self.speed;
		self.x += self.parent.rotation * 10;
	};
});
var SpecialItem = Container.expand(function () {
	var self = Container.call(this);
	var itemGraphics = self.attachAsset('specialItem', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = -2;
	self._move_migrated = function () {
		self.y += self.speed;
	};
});

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

/**** 
* Game Code
****/ 
var bg = game.attachAsset('background', {});
bg.width = 2048;
bg.height = 2732;
bg.alpha = 0.5;
var bg2 = game.attachAsset('background', {});
bg2.width = 2048;
bg2.height = 2732;
bg2.y = -2732;
bg2.alpha = 0.5;
var hero = game.addChild(new Hero());
var healthDisplay = new HealthDisplay();
healthDisplay.y += 50;
LK.gui.topLeft.addChild(healthDisplay);
var enemies = [];
var heroBullets = [];
var enemyBullets = [];
var specialItems = [];
hero.x = 2048 / 2;
hero.y = 2732 - 200;
var spawnEnemy = function spawnEnemy() {
	var enemyType = Math.floor(Math.random() * 3);
	var enemy;
	switch (enemyType) {
		case 0:
			enemy = new Enemy1();
			break;
		case 1:
			enemy = new Enemy2();
			break;
		case 2:
			enemy = new Enemy3();
			break;
	}
	enemy.x = Math.random() * 2048;
	enemy.y = 0;
	enemies.push(enemy);
	game.addChild(enemy);
};
var spawnHeroBullet = function spawnHeroBullet() {
	var bullet = new HeroBullet();
	bullet.x = hero.x;
	bullet.y = hero.y;
	bullet._move_migrated = function () {
		bullet.y -= bullet.speed;
	};
	heroBullets.push(bullet);
	game.addChild(bullet);
};
var spawnSpecialItem = function spawnSpecialItem() {
	var item = new SpecialItem();
	item.x = Math.random() * 2048;
	item.y = 0;
	specialItems.push(item);
	game.addChild(item);
	item.on('down', function () {
		enemyBullets.forEach(function (bullet, index) {
			bullet.destroy();
			enemyBullets.splice(index, 1);
		});
	});
};
var spawnEnemyBullet = function spawnEnemyBullet(enemy) {
	var bullet = new EnemyBullet();
	bullet.x = enemy.x;
	bullet.y = enemy.y;
	bullet._move_migrated = function () {
		bullet.y += bullet.speed;
	};
	enemyBullets.push(bullet);
	game.addChild(bullet);
};
var checkCollision = function checkCollision() {
	specialItems.forEach(function (item, index) {
		if (hero.intersects(item)) {
			item.destroy();
			specialItems.splice(index, 1);
			hero.bulletSpeed = 15;
			LK.setTimeout(function () {
				hero.bulletSpeed = 10;
			}, 4000);
		}
	});
};
var gameOver = function gameOver() {};
LK.on('tick', function () {
	bg.y += 2;
	bg2.y += 2;
	if (bg.y >= 2732) {
		bg.y = -2732;
	}
	if (bg2.y >= 2732) {
		bg2.y = -2732;
	}
	hero._move_migrated();
	healthDisplay.updateHealth(hero.health);
	enemies.forEach(function (enemy, index) {
		enemy._move_migrated();
		if (LK.ticks % 120 === 0 && enemy.y > 0) {
			spawnEnemyBullet(enemy);
		}
		if (enemy.y > 2732) {
			enemy.destroy();
			enemies.splice(index, 1);
		}
	});
	heroBullets.forEach(function (bullet, index) {
		bullet._move_migrated();
		if (bullet.y < 0) {
			bullet.destroy();
			heroBullets.splice(index, 1);
		}
	});
	enemyBullets.forEach(function (bullet, index) {
		bullet._move_migrated();
		if (bullet.y > 2732) {
			bullet.destroy();
			enemyBullets.splice(index, 1);
		}
	});
	specialItems.forEach(function (item, index) {
		item._move_migrated();
		if (item.y > 2732) {
			item.destroy();
			specialItems.splice(index, 1);
		}
	});
	checkCollision();
	heroBullets.forEach(function (bullet, bIndex) {
		enemies.forEach(function (enemy, eIndex) {
			if (bullet.intersects(enemy)) {
				bullet.destroy();
				heroBullets.splice(bIndex, 1);
				var explosion = game.attachAsset('explosion', {
					anchorX: 0.5,
					anchorY: 0.5
				});
				explosion.x = enemy.x;
				explosion.y = enemy.y;
				game.addChild(explosion);
				LK.setTimeout(function () {
					explosion.destroy();
				}, 500);
				enemy.destroy();
				enemies.splice(eIndex, 1);
			}
		});
	});
	enemyBullets.forEach(function (bullet, index) {
		if (hero.intersects(bullet)) {
			bullet.destroy();
			enemyBullets.splice(index, 1);
			hero.health--;
			healthDisplay.updateHealth(hero.health);
			if (hero.health <= 0) {
				LK.showGameOver();
			}
		}
	});
});
LK.on('tick', function () {
	if (LK.ticks % 600 === 0) {
		spawnSpecialItem();
	}
	if (LK.ticks % 384 === 0) {
		spawnEnemy();
	}
});
var dragHero = null;
game.on('down', function (x, y, obj) {
	dragHero = hero;
	if (LK.ticks - hero.lastBulletTime >= 60) {
		hero.lastBulletTime = LK.ticks;
		spawnHeroBullet();
		spawnHeroBullet();
		spawnHeroBullet();
	}
});
game.on('move', function (x, y, obj) {
	if (dragHero) {
		var pos = game.toLocal(obj.global);
		var oldX = dragHero.x;
		dragHero.x = pos.x;
		dragHero.y = pos.y;
		var tilt = (dragHero.x - oldX) * 0.05;
		tilt = Math.max(-0.5, Math.min(0.5, tilt));
		hero.rotation = tilt;
		if (LK.ticks - hero.lastBulletTime >= 60) {
			hero.lastBulletTime = LK.ticks;
			spawnHeroBullet();
			spawnHeroBullet();
			spawnHeroBullet();
		}
	}
});
game.on('up', function (x, y, obj) {
	dragHero = null;
});

===================================================================
--- original.js
+++ change.js
@@ -130,14 +130,14 @@
 ****/ 
 var bg = game.attachAsset('background', {});
 bg.width = 2048;
 bg.height = 2732;
-bg.alpha = 0.75;
+bg.alpha = 0.5;
 var bg2 = game.attachAsset('background', {});
 bg2.width = 2048;
 bg2.height = 2732;
 bg2.y = -2732;
-bg2.alpha = 0.75;
+bg2.alpha = 0.5;
 var hero = game.addChild(new Hero());
 var healthDisplay = new HealthDisplay();
 healthDisplay.y += 50;
 LK.gui.topLeft.addChild(healthDisplay);