/**** 
* Classes
****/
var FrameRateCounter = Container.expand(function () {
	var self = Container.call(this);
	self.lastTime = Date.now();
	self.frameCount = 0;
	self.framerate = 0;
	self.display = new Text2('FPS: 0', {
		size: 150,
		fill: '#000000'
	});
	self.display.anchor.set(1, 0);
	self.updateDisplay = function () {
		self.display.setText('FPS: ' + Math.round(self.framerate).toString());
	};
	self.update = function () {
		var currentTime = Date.now();
		self.frameCount++;
		var elapsedTime = (currentTime - self.lastTime) / 1000;
		if (elapsedTime >= 1) {
			self.framerate = self.frameCount / elapsedTime;
			self.updateDisplay();
			self.frameCount = 0;
			self.lastTime = currentTime;
		}
	};
});
var Bullet = Container.expand(function () {
	var self = Container.call(this);
	self.update = function () {};
});
var Plain = Container.expand(function () {
	var self = Container.call(this);
	var plainGraphics = self.createAsset('correct_plain_asset_id', 'Correct Plain Graphics Description', .5, .5);
	plainGraphics.scale.x = 2;
	plainGraphics.scale.y = 2;
	plainGraphics.alpha = 0;
	self.shoot = function (enemies, bulletsContainer) {
		if (self.cooldownTimer <= 0 && enemies.length > 0) {
			var bullet = new Bullet(self);
			bullet.x = self.x;
			bullet.y = self.y;
			bulletsContainer.addChild(bullet);
			self.cooldownTimer = self.cooldown;
		}
		self.cooldownTimer--;
	};
});
var Tower = Container.expand(function (gameInstance) {
	var self = Container.call(this);
	self.game = gameInstance;
	var towerGraphics = self.createAsset('tower', 'Tower Graphics', .5, .5);
	self.cooldown = 0.625 / 0.7 * (1 / 0.6) * 1.3;
	self.cooldownTimer = 0;
	self.shoot = function (enemies, bullets) {
		this.handleShooting(enemies, bullets);
	};
	self.handleShooting = function (enemies, bullets) {
		self.cooldownTimer--;
		if (self.cooldownTimer <= 0 && enemies.length > 0) {
			self.fireBullet(bullets);
		}
	};
	self.fireBullet = function (bullets) {
		var bullet = new Bullet(self.game);
		bullet.x = self.x;
		bullet.y = self.y;
		gameInstance.bulletsContainer.addChild(bullet);
		gameInstance.bullets.push(bullet);
		self.cooldownTimer = self.cooldown;
	};
});
var Enemy = Container.expand(function (gameInstance) {
	var self = Container.call(this);
	self.game = gameInstance;
	var enemyGraphics = self.createAsset('enemy', 'Enemy Graphics', .5, .5);
	var enemySpeed = 25.6 * 0.7 * 0.6;
	self.move = function () {
		self.y += enemySpeed;
		if (self.y > 2732) {
			self.gameInstance.removeEnemy(self);
		}
	};
	self.updatePosition = function () {
		self.y += enemySpeed;
		if (self.y > 2732) {
			self.gameInstance.removeEnemy(self);
		}
	};
});
var EnemyBullet = Container.expand(function (gameInstance) {
	var self = Container.call(this);
	self.game = gameInstance;
	var bulletGraphics = self.createAsset('enemy_bullet', 'Enemy Bullet Graphics', .5, .5);
	self.update = function () {
		self.x += 240;
		if (self.x > 2098) {
			self.game.removeBullet(self);
		}
	};
});

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

/**** 
* Game Code
****/
game.incrementScore = function () {
	game.score++;
};
game.removeEnemy = function (enemy) {
	var index = game.enemies.indexOf(enemy);
	if (index > -1) {
		enemy.destroy();
		game.enemies.splice(index, 1);
	}
};
game.removeBullet = function (bullet) {
	var index = game.bullets.indexOf(bullet);
	if (index > -1) {
		bullet.destroy();
		game.bullets.splice(index, 1);
	}
};
game.spawnEnemies = function () {
	game.generateEnemies();
};
game.generateEnemies = function () {
	game.enemiesSpawnedLastRound += 10;
	for (var i = 0; i < game.enemiesSpawnedLastRound; i++) {
		var newEnemy = new Enemy(game);
		newEnemy.x = Math.random() * 2048;
		newEnemy.y = -25 * (i + 1);
		game.enemies.push(newEnemy);
		game.addChild(newEnemy);
	}
	game.enemyCounterTxt.setText('Enemies: ' + game.enemies.length.toString());
};
game.updateEnemyCounter = function () {};
game.score = 0;
game.frameRateCounter = new FrameRateCounter();
LK.gui.topRight.addChild(game.frameRateCounter.display);
var enemiesSpawnedLastRound = 1;
game.enemies = [];
game.enemyCounterTxt = new Text2('Enemies: ' + game.enemies.length.toString(), {
	size: 150,
	fill: "#ff0000"
});
game.enemyCounterTxt.anchor.set(0, 1);
LK.gui.bottomLeft.addChild(game.enemyCounterTxt);
game.setBackgroundColor(0xFFFFFF);
var towers = [];
game.bullets = [];
game.bulletsContainer = game.addChild(new Container());
game.enemies = [];
var initialTower = new Tower(game);
initialTower.x = 0 + initialTower.width / 2 - 260;
initialTower.y = 500 + initialTower.height / 2 + 300 + 800 + 500;
towers.push(initialTower);
game.addChild(initialTower);
var plain = game.addChild(new Plain());
plain.x = 2048 / 2;
plain.y = 2732 / 2;
game.addChild(plain);
var enemy = new Enemy();
enemy.x = 2048 / 2;
enemy.y = -enemy.height / 2;
game.enemies.push(enemy);
game.addChild(enemy);
game.on('down', function (obj) {
	var event = obj.event;
	var pos = event.getLocalPosition(game);
	var newTower = new Tower(game);
	newTower.x = pos.x;
	newTower.y = pos.y;
	game.addChild(newTower);
	towers.push(newTower);
});
LK.on('tick', function () {
	game.frameRateCounter.update(enemiesSpawnedLastRound);
	if (game.enemies.length === 0) {
		game.spawnEnemies();
	}
	towers.forEach(function (tower) {
		tower.shoot(game.enemies, game.bullets);
	});
	var activeEnemies = game.enemies.filter(function (enemy) {
		return enemy.y < 2732;
	});
	activeEnemies.forEach(function (enemy) {
		enemy.move();
	});
	var activeBullets = game.bullets.filter(function (bullet) {
		return bullet.x < 2048;
	});
	activeBullets.forEach(function (bullet) {
		bullet.update();
	});
	game.bullets = activeBullets;
});

===================================================================
--- original.js
+++ change.js
@@ -78,15 +78,15 @@
 	var enemySpeed = 25.6 * 0.7 * 0.6;
 	self.move = function () {
 		self.y += enemySpeed;
 		if (self.y > 2732) {
-			self.game.removeEnemy(self);
+			self.gameInstance.removeEnemy(self);
 		}
 	};
 	self.updatePosition = function () {
 		self.y += enemySpeed;
 		if (self.y > 2732) {
-			self.game.removeEnemy(self);
+			self.gameInstance.removeEnemy(self);
 		}
 	};
 });
 var EnemyBullet = Container.expand(function (gameInstance) {