var Star = Container.expand(function () {
	var self = Container.call(this);
	var starGraphics = self.createAsset('star', 'Background star', .5, .5);
	self.move = function () {
		self.y += 1;
		if (self.y > 2732) self.y = 0;
	};
});
var Explosion = Container.expand(function () {
	var self = Container.call(this);
	self.isActive = false;
	self.start = function () {
		self.isActive = true;
		var explosionAnimation = LK.getAsset('explosionAnimation', 'Explosion Animation', .5, .5);
		self.addChild(explosionAnimation);
		LK.setTimeout(function () {
			self.isActive = false;
			self.destroy();
		}, 500);
	};
});
var Hero = Container.expand(function () {
	var self = Container.call(this);
	var heroGraphics = self.createAsset('hero', 'Hero spaceship', .5, .5);
	var moveDelay = 0;
	self.move = function (x) {
		self.x = x;
		self.y = 2732 - 200;
	};
	self.shoot = function () {
		return new HeroBullet(self.x, self.y);
	};
});
var HeroBullet = Container.expand(function (x, y) {
	var self = Container.call(this);
	var bulletGraphics = self.createAsset('heroBullet', 'Hero bullet', .5, .5);
	self.x = x;
	self.y = y;
	self.isActive = true;
	self.move = function () {
		self.y -= 20;
	};
	LK.setTimeout(function () {
		self.destroy();
	}, 3000);
});
var Enemy = Container.expand(function (x, y) {
	var self = Container.call(this);
	var enemyGraphics = self.createAsset('enemy', 'Enemy spaceship', .5, .5);
	self.x = x;
	self.y = y;
	self.move = function () {
		self.y += 2;
		if (self.y > 2732) self.destroy();
		self.x += Math.sin(self.y / 50) * 5;
	};
	self.shoot = function () {};
});
var EnemyBullet = Container.expand(function () {
	var self = Container.call(this);
	var bulletGraphics = self.createAsset('enemyBullet', 'Enemy bullet', .5, .5);
	self.move = function () {};
});
var Asteroid = Container.expand(function () {
	var self = Container.call(this);
	var size = (Math.random() * 1 + 0.5) * 1.3;
	var asteroidGraphics = self.createAsset('asteroid', 'Asteroid', size, size);
	self.direction = Math.random() * 2 - 1;
	self.move = function () {
		self.y += 5;
		self.x += self.direction;
	};
});
var Game = Container.expand(function () {
	var self = Container.call(this);
	var fpsCounter = new Text2('FPS: 0', {
		size: 50,
		fill: '#ffffff',
		font: 'Arial Bold'
	});
	LK.gui.topLeft.addChild(fpsCounter);
	var scoreText = new Text2('Score: 0', {
		size: 50,
		fill: '#ffffff',
		font: 'Arial Bold'
	});
	LK.gui.topLeft.addChild(scoreText);
	scoreText.y = fpsCounter.height;
	var frameCount = 0;
	var lastTime = Date.now();
	LK.on('tick', function () {
		frameCount++;
		var currentTime = Date.now();
		var deltaTime = currentTime - lastTime;
		if (deltaTime >= 1000) {
			var fps = Math.round(frameCount / deltaTime * 1000);
			fpsCounter.setText('FPS: ' + fps);
			scoreText.setText('Score: ' + score);
			frameCount = 0;
			lastTime = currentTime;
		}
	});
	var score = 0;
	var lives = 3;
	var heroes = [];
	var heroBullets = [];
	var enemies = [];
	var enemyBullets = [];
	var asteroids = [];
	var stars = [];
	for (var i = 0; i < 100; i++) {
		var star = new Star();
		star.x = Math.random() * 2048;
		star.y = Math.random() * 2732;
		self.addChild(star);
		stars.push(star);
	}
	var hero = self.addChild(new Hero());
	hero.x = 2048 / 2;
	hero.y = 2732 - 200;
	heroes.push(hero);
	var heartIcon = LK.getAsset('heart', 'Heart icon', .5, .5);
	var heartIcons = [];
	for (var i = 0; i < lives; i++) {
		var heart = LK.getAsset('heart', 'Heart icon', .5, .5);
		heart.x = 2048 / 3 - lives * heart.width / 2 + i * heart.width + 100;
		heart.y = 50;
		LK.gui.topLeft.addChild(heart);
		heartIcons.push(heart);
	}
	stage.on('move', function (obj) {
		var event = obj.event;
		var pos = event.getLocalPosition(self);
		hero.move(pos.x);
	});
	var canShoot = true;
	var shooting = false;
	var shootInterval;
	stage.on('down', function (obj) {
		shooting = true;
		if (canShoot) {
			var bullet;
			bullet = hero.shoot();
			bullet.x = hero.x;
			bullet.y = hero.y;
			self.addChild(bullet);
			heroBullets.push(bullet);
			canShoot = false;
		}
		shootInterval = LK.setInterval(function () {
			if (shooting) {
				var bullet;
				bullet = hero.shoot();
				bullet.x = hero.x;
				bullet.y = hero.y;
				self.addChild(bullet);
				heroBullets.push(bullet);
			}
		}, 200);
	});
	stage.on('up', function (obj) {
		shooting = false;
		LK.clearInterval(shootInterval);
	});
	for (var i = heroBullets.length - 1; i >= 0; i--) {
		if (heroBullets[i].y < 0) {
			heroBullets[i].destroy();
			heroBullets.splice(i, 1);
		}
	}
	var enemySpawnTimer = 0;
	var asteroidSpawnTimer = 0;
	LK.on('tick', function () {
		if (enemySpawnTimer++ % Math.floor(Math.random() * 300) == 0 && enemies.length < 45) {
			var enemyCount = Math.floor(Math.random() * 5);
			var enemySpacing = 2048 / (enemyCount + 1);
			for (var i = 0; i < enemyCount; i++) {
				var enemy = new Enemy((i + 1) * enemySpacing, 0);
				self.addChild(enemy);
				enemies.push(enemy);
			}
		}
		for (var i = enemies.length - 1; i >= 0; i--) {
			if (enemies[i].y > 2732) {
				enemies[i].destroy();
				enemies.splice(i, 1);
			}
		}
		if (asteroidSpawnTimer++ % (Math.floor(Math.random() * 100) + 30) == 0) {
			var asteroid;
			asteroid = new Asteroid();
			asteroid.x = Math.random() * 2048;
			asteroid.y = 0;
			asteroid.size = Math.random() * 2 + 0.5;
			self.addChild(asteroid);
			asteroids.push(asteroid);
		}
		for (var i = 0; i < enemies.length; i++) {
			enemies[i].move();
			if (enemies[i].y >= hero.y) {
				LK.showGameOver();
			}
		}
		for (var i = 0; i < stars.length; i++) {
			stars[i].move();
		}
		for (var i = asteroids.length - 1; i >= 0; i--) {
			asteroids[i].move();
			if (asteroids[i].y > 2732) {
				asteroids[i].destroy();
				asteroids.splice(i, 1);
			} else if (hero.intersects(asteroids[i])) {
				lives--;
				if (heartIcons.length > 0) {
					var lastHeart = heartIcons.pop();
					lastHeart.destroy();
				}
				var explosion = new Explosion();
				explosion.x = hero.x;
				explosion.y = hero.y;
				self.addChild(explosion);
				explosion.start();
				if (lives <= 0) {
					LK.showGameOver();
				} else {
					asteroids[i].destroy();
					asteroids.splice(i, 1);
				}
			}
		}
		for (var i = heroBullets.length - 1; i >= 0; i--) {
			heroBullets[i].move();
			if (heroBullets[i].y < 0 || heroBullets[i].y > 2732) {
				heroBullets[i].destroy();
				heroBullets.splice(i, 1);
				continue;
			}
			for (var n = 0; n < enemies.length; n++) {
				if (heroBullets[i] && heroBullets[i].intersects(enemies[n])) {
					var explosion = new Explosion();
					explosion.x = enemies[n].x;
					explosion.y = enemies[n].y;
					self.addChild(explosion);
					explosion.start();
					if (enemies[n]) {
						enemies[n].destroy();
						enemies.splice(n, 1);
					}
					heroBullets[i].destroy();
					heroBullets.splice(i, 1);
					score += 10;
					scoreText.setText('Score: ' + score);
					break;
				}
			}
		}
		for (var i = 0; i < enemyBullets.length; i++) {
			enemyBullets[i].move();
		}
	});
});

===================================================================
--- original.js
+++ change.js
@@ -62,9 +62,9 @@
 	self.move = function () {};
 });
 var Asteroid = Container.expand(function () {
 	var self = Container.call(this);
-	var size = Math.random() * 1 + 0.5;
+	var size = (Math.random() * 1 + 0.5) * 1.3;
 	var asteroidGraphics = self.createAsset('asteroid', 'Asteroid', size, size);
 	self.direction = Math.random() * 2 - 1;
 	self.move = function () {
 		self.y += 5;