var HeroBullet = Container.expand(function () {
	var self = Container.call(this);
	var bulletGraphics = self.createAsset('heroBullet', 'Hero Bullet Graphics', .5, .5);
	self.speed = 10;
	self.move = function () {
		self.x += self.speed;
		if (self.x > 2048) {
			self.destroy();
		}
	};
});
var EnemyBullet = Container.expand(function () {
	var self = Container.call(this);
	var bulletGraphics = self.createAsset('enemyBullet', 'Enemy Bullet Graphics', .5, .5);
	self.speed = -10;
	self.move = function () {
		self.x += self.speed;
	};
});
var Hero = Container.expand(function () {
	var self = Container.call(this);
	var heroGraphics = self.createAsset('hero', 'Hero Graphics', .5, .5);
	self.hitPoints = 5;
	self.takeDamage = function () {
		self.hitPoints--;
		hitPointsTxt.setText(self.hitPoints.toString());
		if (self.hitPoints <= 0) {
			LK.showGameOver();
		}
	};
});
var Enemy = Container.expand(function () {
	var self = Container.call(this);
	var enemyGraphics = self.createAsset('enemy', 'Enemy Graphics', .5, .5);
});
var Game = Container.expand(function () {
	var self = Container.call(this);
	var heroBullets = [];
	var enemyBullets = [];
	var enemies = [];
	var hero = self.addChild(new Hero());
	hero.x = hero.width;
	hero.y = 2732 / 2;
	var hitPointsTxt;
	hitPointsTxt = new Text2('5', {
		size: 150,
		fill: '#ffffff'
	});
	hitPointsTxt.anchor.set(0, 0);
	LK.gui.topLeft.addChild(hitPointsTxt);
	LK.on('tick', function () {
		for (var i = 0; i < heroBullets.length; i++) {
			heroBullets[i].move();
			if (heroBullets[i].x > 2048) {
				heroBullets[i].destroy();
				heroBullets.splice(i, 1);
			}
		}
		for (var i = 0; i < enemyBullets.length; i++) {
			enemyBullets[i].move();
			if (enemyBullets[i].x < 0) {
				enemyBullets[i].destroy();
				enemyBullets.splice(i, 1);
			}
		}
		for (var i = 0; i < enemies.length; i++) {
			enemies[i].x -= 10;
			if (enemies[i].x + enemies[i].width < 0) {
				enemies[i].destroy();
				enemies.splice(i, 1);
			}
			if (hero.intersects(enemies[i])) {
				hero.takeDamage();
				enemies[i].destroy();
				enemies.splice(i, 1);
			}
		}
		if (LK.ticks % 60 == 0) {
			var enemy = new Enemy();
			enemy.x = 2048;
			enemy.y = Math.random() * (2732 - enemy.height);
			enemies.push(enemy);
			self.addChild(enemy);
		}
		stage.on('down', function (obj) {
			var bullet = new HeroBullet();
			bullet.x = hero.x;
			bullet.y = hero.y;
			heroBullets.push(bullet);
			self.addChild(bullet);
		});
	});
	stage.on('down', function (obj) {
		var pos = obj.event.getLocalPosition(self);
		hero.y = pos.y;
	});
});

===================================================================
--- original.js
+++ change.js
@@ -40,9 +40,10 @@
 	var enemies = [];
 	var hero = self.addChild(new Hero());
 	hero.x = hero.width;
 	hero.y = 2732 / 2;
-	var hitPointsTxt = new Text2('5', {
+	var hitPointsTxt;
+	hitPointsTxt = new Text2('5', {
 		size: 150,
 		fill: '#ffffff'
 	});
 	hitPointsTxt.anchor.set(0, 0);