===================================================================
--- original.js
+++ change.js
@@ -39,29 +39,9 @@
 	self.move = function (x, y) {
 		self.x = x;
 		self.y = y;
 	};
-	self.shoot = function () {
-		var bullet = new HeroBullet();
-		bullet.x = self.x;
-		bullet.y = self.y - 50; // Shoot from above the hero
-		game.addChild(bullet);
-		heroBullets.push(bullet);
-	};
 });
-// HeroBullet class
-var HeroBullet = Container.expand(function () {
-	var self = Container.call(this);
-	var bulletGraphics = self.attachAsset('heroBullet', {
-		anchorX: 0.5,
-		anchorY: 0.5
-	});
-	bulletGraphics.tint = 0x90EE90;
-	self.speed = -10;
-	self.move = function () {
-		self.y += self.speed;
-	};
-});
 
 /**** 
 * Initialize Game
 ****/ 
@@ -75,9 +55,8 @@
 // Global variables
 var hero = new Hero();
 hero.x = 1024; // Center horizontally
 hero.y = 2500; // Near the bottom
-var heroBullets = [];
 var enemies = [];
 var enemyBullets = [];
 // Add hero to the game
 game.addChild(hero);
@@ -88,17 +67,8 @@
 	hero.shoot();
 });
 // Game tick event
 LK.on('tick', function () {
-	// Move hero bullets
-	for (var i = heroBullets.length - 1; i >= 0; i--) {
-		heroBullets[i].move();
-		if (heroBullets[i].y < 0) {
-			// Bullet off-screen
-			heroBullets[i].destroy();
-			heroBullets.splice(i, 1);
-		}
-	}
 	// Move enemies and enemy bullets
 	for (var j = enemies.length - 1; j >= 0; j--) {
 		enemies[j].move();
 		if (enemies[j].y > 2732) {
@@ -118,20 +88,8 @@
 		if (hero.intersects(enemyBullets[k])) {
 			LK.effects.flashScreen(0xff0000, 1000);
 			LK.showGameOver();
 		}
-		// Check collision between hero bullets and enemies
-		for (var i = heroBullets.length - 1; i >= 0; i--) {
-			for (var j = enemies.length - 1; j >= 0; j--) {
-				if (heroBullets[i].intersects(enemies[j])) {
-					enemies[j].destroy();
-					enemies.splice(j, 1);
-					heroBullets[i].destroy();
-					heroBullets.splice(i, 1);
-					break;
-				}
-			}
-		}
 	}
 	// Spawn enemies and bullets
 	if (LK.ticks % 120 == 0) {
 		// Every 2 seconds