/**** 
* Classes
****/
var GoldenBadge = Container.expand(function () {
	var self = Container.call(this);
	self.on('down', function (obj) {
		self.destroy();
		LK.resumeGame();
	});
	self.attachAsset('goldenBadge', {
		anchorX: 0.5,
		anchorY: 0.5
	});
});
// Hero class
var Hero = Container.expand(function () {
	var self = Container.call(this);
	var heroGraphics = self.attachAsset('hero', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.shoot = function () {
		var bullet = new HeroBullet();
		bullet.x = self.x;
		bullet.y = self.y - self.height / 2;
		game.addChild(bullet);
		heroBullets.push(bullet);
	};
});
// Enemy class
var Enemy = Container.expand(function () {
	var self = Container.call(this);
	var enemyGraphics = self.attachAsset('enemy', {
		anchorX: 0.5,
		anchorY: 0.5,
		scaleX: 2,
		scaleY: 2
	});
	self.health = 2;
	self.move = function () {
		self.y += 2;
		if (self.y > 2732 + self.height) {
			self.destroy();
			enemies.splice(enemies.indexOf(self), 1);
			LK.effects.flashScreen(0xff0000, 1000);
			LK.showGameOver();
		}
	};
});
// HeroBullet class
var HeroBullet = Container.expand(function () {
	var self = Container.call(this);
	var bulletGraphics = self.attachAsset('heroBullet', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.move = function () {
		self.y -= 10;
		if (self.y < -self.height) {
			self.destroy();
			heroBullets.splice(heroBullets.indexOf(self), 1);
		}
	};
});
// EnemyBullet class
var EnemyBullet = Container.expand(function () {
	var self = Container.call(this);
	var bulletGraphics = self.attachAsset('enemyBullet', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.move = function () {
		self.y += 5;
		if (self.y > 2732 + self.height) {
			self.destroy();
			enemyBullets.splice(enemyBullets.indexOf(self), 1);
		}
	};
});

/**** 
* Initialize Game
****/
var game = new LK.Game({
	backgroundImage: 'space' // Init game with space background
});

/**** 
* Game Code
****/
// Define the assets for the hero, enemy robots, and bullets
// Initialize hero
var hero = game.addChild(new Hero());
hero.x = 2048 / 2;
hero.y = 2732 - 100;
// Initialize enemy and bullet arrays
var enemies = [];
var heroBullets = [];
var enemyBullets = [];
// Handle shooting and moving the hero
game.on('down', function (obj) {
	hero.shoot();
});
// Handle swipe
game.on('move', function (obj) {
	var event = obj.event;
	var pos = event.getLocalPosition(game);
	hero.x = pos.x;
});
// Initialize 20 minutes timer
var timer = 20 * 60;
// Create a timer text object
var timerTxt = new Text2('20:00', {
	size: 100,
	fill: '#ffffff'
});
// Attach the timer text object to the top right corner of the screen
LK.gui.topRight.addChild(timerTxt);
// Game tick event
LK.on('tick', function () {
	// Update timer every second
	if (LK.ticks % 60 == 0) {
		timer--;
		// Update timer text
		var minutes = Math.floor(timer / 60);
		var seconds = timer % 60;
		timerTxt.setText(minutes + ':' + (seconds < 10 ? '0' : '') + seconds);
	}
	// Move hero bullets
	for (var i = heroBullets.length - 1; i >= 0; i--) {
		heroBullets[i].move();
	}
	// Move enemy bullets
	for (var j = enemyBullets.length - 1; j >= 0; j--) {
		enemyBullets[j].move();
	}
	// Move enemies and randomly shoot
	for (var k = enemies.length - 1; k >= 0; k--) {
		enemies[k].move();
	}
	// Spawn enemies
	if (LK.ticks % 120 == 0) {
		var enemy = new Enemy();
		enemy.x = Math.random() * (2048 - enemy.width) + enemy.width / 2;
		enemy.y = -enemy.height;
		game.addChild(enemy);
		enemies.push(enemy);
	}
	if (LK.ticks % 72000 == 0 && enemies.length == 0) {
		var goldenBadge = new GoldenBadge();
		goldenBadge.x = 2048 / 2;
		goldenBadge.y = 2732 / 2;
		game.addChild(goldenBadge);
		LK.pauseGame();
	}
	// Check for collisions between hero bullets and enemies
	for (var h = heroBullets.length - 1; h >= 0; h--) {
		for (var e = enemies.length - 1; e >= 0; e--) {
			if (heroBullets[h].intersects(enemies[e])) {
				heroBullets[h].destroy();
				heroBullets.splice(h, 1);
				enemies[e].health--;
				if (enemies[e].health <= 0) {
					enemies[e].destroy();
					enemies.splice(e, 1);
				}
				break;
			}
		}
	}
	// Check for collisions between enemy bullets and hero
	for (var eb = enemyBullets.length - 1; eb >= 0; eb--) {
		if (enemyBullets[eb].intersects(hero)) {
			// Flash screen red for 1 second (1000ms) to show damage taken
			LK.effects.flashScreen(0xff0000, 1000);
			// Show game over
			LK.showGameOver();
			break;
		}
	}
});

===================================================================
--- original.js
+++ change.js
@@ -35,8 +35,9 @@
 		anchorY: 0.5,
 		scaleX: 2,
 		scaleY: 2
 	});
+	self.health = 2;
 	self.move = function () {
 		self.y += 2;
 		if (self.y > 2732 + self.height) {
 			self.destroy();
@@ -86,10 +87,10 @@
 
 /**** 
 * Game Code
 ****/
-// Initialize hero
 // Define the assets for the hero, enemy robots, and bullets
+// Initialize hero
 var hero = game.addChild(new Hero());
 hero.x = 2048 / 2;
 hero.y = 2732 - 100;
 // Initialize enemy and bullet arrays
@@ -157,10 +158,13 @@
 		for (var e = enemies.length - 1; e >= 0; e--) {
 			if (heroBullets[h].intersects(enemies[e])) {
 				heroBullets[h].destroy();
 				heroBullets.splice(h, 1);
-				enemies[e].destroy();
-				enemies.splice(e, 1);
+				enemies[e].health--;
+				if (enemies[e].health <= 0) {
+					enemies[e].destroy();
+					enemies.splice(e, 1);
+				}
 				break;
 			}
 		}
 	}