/**** 
* Classes
****/ 
var Bullet = Container.expand(function (damage) {
	var self = Container.call(this);
	var bulletGraphics = self.attachAsset('bullet', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.vx = 0;
	self.vy = 0;
	self.damage = damage || 10;
	self.lifetime = 60; // Bullets disappear after 1 second
	self.update = function () {
		// Move bullet
		self.x += self.vx;
		self.y += self.vy;
		// Decrease lifetime
		self.lifetime--;
		return self.lifetime <= 0;
	};
	return self;
});
var Explosion = Container.expand(function () {
	var self = Container.call(this);
	var explosionGraphics = self.attachAsset('explosion', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.lifetime = 15;
	self.scale.set(0.2);
	self.update = function () {
		self.lifetime--;
		self.scale.set(1 - self.lifetime / 20);
		self.alpha = self.lifetime / 15;
		return self.lifetime <= 0;
	};
	return self;
});
var ManualTarget = Container.expand(function () {
	var self = Container.call(this);
	var targetGraphics = self.attachAsset('manualTarget', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.lifetime = 15;
	self.alpha = 0.5;
	self.update = function () {
		self.lifetime--;
		self.alpha = self.lifetime / 15;
		self.rotation += 0.1;
		return self.lifetime <= 0;
	};
	return self;
});
var Tower = Container.expand(function () {
	var self = Container.call(this);
	// Tower base (doesn't rotate)
	var base = self.attachAsset('towerBase', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	// Tower turret (rotates to aim)
	var turret = new Container();
	var turretGraphics = turret.attachAsset('tower', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.addChild(turret);
	// Tower stats
	self.health = 100;
	self.maxHealth = 100;
	self.damage = 10;
	self.fireRate = 60; // frames between shots
	self.fireTimer = 0;
	self.range = 800;
	self.upgradeLevel = {
		damage: 1,
		fireRate: 1,
		range: 1,
		health: 1
	};
	// Health bar
	var healthBarContainer = new Container();
	var healthBarBg = healthBarContainer.attachAsset('healthBarBg', {
		anchorX: 0.5,
		anchorY: 0.5,
		width: 200
	});
	var healthBarFill = new Container();
	var healthBarGraphics = healthBarFill.attachAsset('healthBar', {
		anchorX: 0,
		anchorY: 0.5,
		width: 200
	});
	healthBarContainer.addChild(healthBarFill);
	healthBarContainer.y = -150;
	self.addChild(healthBarContainer);
	// Methods
	self.update = function () {
		// Decrease fire timer
		if (self.fireTimer > 0) {
			self.fireTimer--;
		}
		// Update health bar
		healthBarFill.scale.x = self.health / self.maxHealth;
		// Find target if none currently
		var target = null;
		var closestDist = self.range;
		for (var i = 0; i < zombies.length; i++) {
			var zombie = zombies[i];
			var dx = zombie.x - self.x;
			var dy = zombie.y - self.y;
			var dist = Math.sqrt(dx * dx + dy * dy);
			if (dist < closestDist) {
				closestDist = dist;
				target = zombie;
			}
		}
		// Aim at target
		if (target) {
			var angle = Math.atan2(target.y - self.y, target.x - self.x);
			turret.rotation = angle;
			// Fire if ready
			if (self.fireTimer <= 0) {
				var bullet = new Bullet(self.damage);
				bullet.x = self.x;
				bullet.y = self.y;
				bullet.rotation = angle;
				bullet.vx = Math.cos(angle) * 15;
				bullet.vy = Math.sin(angle) * 15;
				game.addChild(bullet);
				bullets.push(bullet);
				self.fireTimer = self.fireRate;
				LK.getSound('shoot').play();
			}
		}
	};
	self.manualShoot = function (x, y) {
		var angle = Math.atan2(y - self.y, x - self.x);
		turret.rotation = angle;
		var bullet = new Bullet(self.damage * 2); // Manual shots do double damage
		bullet.x = self.x;
		bullet.y = self.y;
		bullet.rotation = angle;
		bullet.vx = Math.cos(angle) * 15;
		bullet.vy = Math.sin(angle) * 15;
		game.addChild(bullet);
		bullets.push(bullet);
		LK.getSound('shoot').play();
	};
	self.takeDamage = function (amount) {
		self.health -= amount;
		// Flash the tower when hit
		LK.effects.flashObject(self, 0xff0000, 300);
		LK.getSound('towerHit').play();
		if (self.health <= 0) {
			return true; // Tower destroyed
		}
		return false;
	};
	self.upgradeDamage = function () {
		self.upgradeLevel.damage++;
		self.damage += 5;
		LK.getSound('upgrade').play();
	};
	self.upgradeFireRate = function () {
		self.upgradeLevel.fireRate++;
		self.fireRate = Math.max(10, self.fireRate - 10);
		LK.getSound('upgrade').play();
	};
	self.upgradeRange = function () {
		self.upgradeLevel.range++;
		self.range += 100;
		LK.getSound('upgrade').play();
	};
	self.upgradeHealth = function () {
		self.upgradeLevel.health++;
		var oldMaxHealth = self.maxHealth;
		self.maxHealth += 50;
		self.health += self.maxHealth - oldMaxHealth;
		LK.getSound('upgrade').play();
	};
	return self;
});
var UpgradePanel = Container.expand(function (tower) {
	var self = Container.call(this);
	// Panel background
	var panel = self.attachAsset('upgradePanel', {
		anchorX: 0,
		anchorY: 0
	});
	// Title
	var title = new Text2("UPGRADES", {
		size: 60,
		fill: 0xffffff
	});
	title.x = 250;
	title.y = 100;
	title.anchor.set(0.5);
	self.addChild(title);
	// Gold display
	var goldIcon = new Container();
	var goldIconGraphics = goldIcon.attachAsset('goldIcon', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	goldIcon.x = 100;
	goldIcon.y = 200;
	self.addChild(goldIcon);
	var goldText = new Text2("0", {
		size: 50,
		fill: 0xffcc00
	});
	goldText.x = 180;
	goldText.y = 200;
	goldText.anchor.set(0, 0.5);
	self.addChild(goldText);
	// Upgrade buttons
	var upgrades = [{
		name: "Damage",
		action: "upgradeDamage",
		cost: 50,
		desc: "+5 damage per shot"
	}, {
		name: "Fire Rate",
		action: "upgradeFireRate",
		cost: 75,
		desc: "Shoot faster"
	}, {
		name: "Range",
		action: "upgradeRange",
		cost: 100,
		desc: "+100 targeting range"
	}, {
		name: "Health",
		action: "upgradeHealth",
		cost: 150,
		desc: "+50 max health"
	}];
	var buttons = [];
	for (var i = 0; i < upgrades.length; i++) {
		var y = 300 + i * 150;
		var button = new Container();
		var buttonGraphics = button.attachAsset('upgradeButton', {
			anchorX: 0.5,
			anchorY: 0.5
		});
		button.x = 250;
		button.y = y;
		var nameText = new Text2(upgrades[i].name, {
			size: 40,
			fill: 0xffffff
		});
		nameText.x = 0;
		nameText.y = -30;
		nameText.anchor.set(0.5);
		button.addChild(nameText);
		var costText = new Text2(upgrades[i].cost + " gold", {
			size: 30,
			fill: 0xffcc00
		});
		costText.x = 0;
		costText.y = 0;
		costText.anchor.set(0.5);
		button.addChild(costText);
		var descText = new Text2(upgrades[i].desc, {
			size: 25,
			fill: 0xcccccc
		});
		descText.x = 0;
		descText.y = 30;
		descText.anchor.set(0.5);
		button.addChild(descText);
		button.upgrade = upgrades[i];
		buttons.push(button);
		self.addChild(button);
	}
	// Wave info
	var waveInfo = new Container();
	var waveInfoGraphics = waveInfo.attachAsset('waveIndicator', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	waveInfo.x = 250;
	waveInfo.y = 1000;
	self.addChild(waveInfo);
	var waveText = new Text2("WAVE 1", {
		size: 40,
		fill: 0xffffff
	});
	waveText.x = 0;
	waveText.y = 0;
	waveText.anchor.set(0.5);
	waveInfo.addChild(waveText);
	// Stats display
	var statsTitle = new Text2("TOWER STATS", {
		size: 50,
		fill: 0xffffff
	});
	statsTitle.x = 250;
	statsTitle.y = 1200;
	statsTitle.anchor.set(0.5);
	self.addChild(statsTitle);
	var stats = [{
		name: "Damage",
		getValue: function getValue() {
			return tower.damage;
		}
	}, {
		name: "Fire Rate",
		getValue: function getValue() {
			return (60 / tower.fireRate).toFixed(1) + "/sec";
		}
	}, {
		name: "Range",
		getValue: function getValue() {
			return tower.range;
		}
	}, {
		name: "Health",
		getValue: function getValue() {
			return tower.health + "/" + tower.maxHealth;
		}
	}];
	var statTexts = [];
	for (var j = 0; j < stats.length; j++) {
		var statY = 1300 + j * 70;
		var statName = new Text2(stats[j].name + ":", {
			size: 35,
			fill: 0xcccccc
		});
		statName.x = 100;
		statName.y = statY;
		statName.anchor.set(0, 0.5);
		self.addChild(statName);
		var statValue = new Text2("0", {
			size: 35,
			fill: 0xffffff
		});
		statValue.x = 400;
		statValue.y = statY;
		statValue.anchor.set(1, 0.5);
		statValue.getValue = stats[j].getValue;
		statTexts.push(statValue);
		self.addChild(statValue);
	}
	// Methods
	self.updateGold = function (amount) {
		goldText.setText(amount.toString());
		// Update button states based on available gold
		for (var i = 0; i < buttons.length; i++) {
			var button = buttons[i];
			// Make buttons grey if can't afford
			if (button.upgrade.cost > amount) {
				button.getChildAt(0).tint = 0x888888;
			} else {
				button.getChildAt(0).tint = 0xffffff;
			}
		}
	};
	self.updateWave = function (wave) {
		waveText.setText("WAVE " + wave);
	};
	self.update = function () {
		// Update stat displays
		for (var i = 0; i < statTexts.length; i++) {
			statTexts[i].setText(statTexts[i].getValue());
		}
	};
	self.checkUpgradeClick = function (x, y, gold) {
		for (var i = 0; i < buttons.length; i++) {
			var button = buttons[i];
			var dx = x - (button.x + self.x);
			var dy = y - (button.y + self.y);
			var dist = Math.sqrt(dx * dx + dy * dy);
			if (dist < 200) {
				// Check if can afford
				if (gold >= button.upgrade.cost) {
					tower[button.upgrade.action]();
					return button.upgrade.cost;
				}
			}
		}
		return 0;
	};
	return self;
});
var Zombie = Container.expand(function (level) {
	var self = Container.call(this);
	// Scale difficulty with level
	level = level || 1;
	// Zombie graphics
	var zombieGraphics = self.attachAsset('zombie', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	// Randomize color slightly
	var green = 0x00ff00;
	var colorVariation = Math.floor(Math.random() * 0x303030);
	zombieGraphics.tint = green - colorVariation;
	// Health bar
	var healthBarContainer = new Container();
	var healthBarBg = healthBarContainer.attachAsset('healthBarBg', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	var healthBarFill = new Container();
	var healthBarGraphics = healthBarFill.attachAsset('healthBar', {
		anchorX: 0,
		anchorY: 0.5
	});
	healthBarContainer.addChild(healthBarFill);
	healthBarContainer.y = -50;
	self.addChild(healthBarContainer);
	// Zombie stats
	self.health = 20 + level * 5;
	self.maxHealth = self.health;
	self.damage = 5 + level;
	self.speed = 1 + level * 0.1;
	self.value = 5 + level; // Gold value
	// Update
	self.update = function (tower) {
		// Move towards tower
		var dx = tower.x - self.x;
		var dy = tower.y - self.y;
		var dist = Math.sqrt(dx * dx + dy * dy);
		// Normalize and apply speed
		if (dist > 0) {
			self.x += dx / dist * self.speed;
			self.y += dy / dist * self.speed;
			// Rotate zombie to face movement direction
			self.rotation = Math.atan2(dy, dx);
		}
		// Update health bar
		healthBarFill.scale.x = self.health / self.maxHealth;
		// Attack tower if close enough
		if (dist < 150) {
			if (tower.takeDamage(self.damage / 60)) {
				// Damage per second
				return "gameover";
			}
		}
		return false;
	};
	self.takeDamage = function (amount) {
		self.health -= amount;
		// Flash when hit
		LK.effects.flashObject(self, 0xffffff, 100);
		if (self.health <= 0) {
			return true; // Zombie destroyed
		}
		return false;
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x001100
});

/**** 
* Game Code
****/ 
// Constants
var GAME_WIDTH = 2048;
var GAME_HEIGHT = 2732;
var CENTER_X = GAME_WIDTH / 2;
var CENTER_Y = GAME_HEIGHT / 2;
// Game variables
var tower;
var upgradePanel;
var bullets = [];
var zombies = [];
var explosions = [];
var targets = [];
var gold = 100;
var wave = 1;
var zombiesKilled = 0;
var waveSize = 10;
var zombiesInWave = 0;
var waveInterval = 0;
var isGameActive = false;
var manualCooldown = 0;
function startGame() {
	// Play background music
	LK.playMusic('background', {
		loop: true
	});
	// Create background
	var background = game.attachAsset('background', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	background.x = CENTER_X;
	background.y = CENTER_Y;
	// Create tower
	tower = new Tower();
	tower.x = CENTER_X;
	tower.y = CENTER_Y;
	game.addChild(tower);
	// Create upgrade panel
	upgradePanel = new UpgradePanel(tower);
	upgradePanel.x = GAME_WIDTH - 500;
	upgradePanel.y = 0;
	game.addChild(upgradePanel);
	// Initialize UI
	upgradePanel.updateGold(gold);
	upgradePanel.updateWave(wave);
	// Start first wave
	startWave();
	isGameActive = true;
}
function startWave() {
	waveSize = 10 + wave * 5;
	zombiesInWave = waveSize;
	waveInterval = Math.max(30, 120 - wave * 5); // Spawn interval decreases with each wave
	upgradePanel.updateWave(wave);
	LK.getSound('waveStart').play();
	// Flash wave indicator
	var waveText = new Text2("WAVE " + wave + " INCOMING!", {
		size: 80,
		fill: 0xff0000
	});
	waveText.x = CENTER_X;
	waveText.y = 200;
	waveText.anchor.set(0.5);
	game.addChild(waveText);
	// Fade out wave text
	var fadeInterval = LK.setInterval(function () {
		waveText.alpha -= 0.02;
		if (waveText.alpha <= 0) {
			waveText.destroy();
			LK.clearInterval(fadeInterval);
		}
	}, 30);
}
function spawnZombie() {
	if (zombiesInWave <= 0) {
		return;
	}
	var zombie = new Zombie(wave);
	// Spawn at random edge position
	var angle = Math.random() * Math.PI * 2;
	var distance = 1200; // Spawn outside visible area
	zombie.x = CENTER_X + Math.cos(angle) * distance;
	zombie.y = CENTER_Y + Math.sin(angle) * distance;
	game.addChild(zombie);
	zombies.push(zombie);
	zombiesInWave--;
}
function gameOver() {
	isGameActive = false;
	// Play game over sound
	LK.getSound('gameOver').play();
	// Display message
	var gameOverText = new Text2("GAME OVER!", {
		size: 120,
		fill: 0xff0000
	});
	gameOverText.x = CENTER_X;
	gameOverText.y = CENTER_Y;
	gameOverText.anchor.set(0.5);
	game.addChild(gameOverText);
	var scoreText = new Text2("Waves Survived: " + wave + "\nZombies Killed: " + zombiesKilled, {
		size: 60,
		fill: 0xffffff
	});
	scoreText.x = CENTER_X;
	scoreText.y = CENTER_Y + 150;
	scoreText.anchor.set(0.5);
	game.addChild(scoreText);
	// Set final score (waves survived * zombies killed)
	LK.setScore(wave * zombiesKilled);
	// Show game over screen after delay
	LK.setTimeout(function () {
		LK.showGameOver();
	}, 3000);
}
/**** 
* Event Handlers
****/ 
game.on('down', function (x, y, obj) {
	if (!isGameActive) {
		return;
	}
	var event = obj;
	var pos = game.toLocal(event.global);
	// Check if clicking on upgrade panel
	if (pos.x > GAME_WIDTH - 500) {
		var upgradeCost = upgradePanel.checkUpgradeClick(pos.x, pos.y, gold);
		if (upgradeCost > 0) {
			gold -= upgradeCost;
			upgradePanel.updateGold(gold);
		}
	} else {
		// Manual targeting - can only fire once per second
		if (manualCooldown <= 0) {
			// Create target indicator
			var target = new ManualTarget();
			target.x = pos.x;
			target.y = pos.y;
			game.addChild(target);
			targets.push(target);
			// Fire at clicked location
			tower.manualShoot(pos.x, pos.y);
			manualCooldown = 60; // 1 second cooldown
		}
	}
});
/**** 
* Game Loop
****/ 
LK.on('tick', function () {
	if (!isGameActive) {
		return;
	}
	// Update tower
	tower.update();
	// Update upgrade panel
	upgradePanel.update();
	// Update bullets
	for (var i = bullets.length - 1; i >= 0; i--) {
		if (bullets[i].update()) {
			bullets[i].destroy();
			bullets.splice(i, 1);
			continue;
		}
		// Check for zombie hits
		for (var j = zombies.length - 1; j >= 0; j--) {
			if (bullets[i] && bullets[i].intersects(zombies[j])) {
				if (zombies[j].takeDamage(bullets[i].damage)) {
					// Zombie killed
					var explosion = new Explosion();
					explosion.x = zombies[j].x;
					explosion.y = zombies[j].y;
					game.addChild(explosion);
					explosions.push(explosion);
					// Add gold
					gold += zombies[j].value;
					upgradePanel.updateGold(gold);
					// Show gold pop-up
					var goldPop = new Text2("+" + zombies[j].value, {
						size: 30,
						fill: 0xffcc00
					});
					goldPop.x = zombies[j].x;
					goldPop.y = zombies[j].y - 50;
					goldPop.anchor.set(0.5);
					game.addChild(goldPop);
					// Fade out gold text
					var fadeInterval = LK.setInterval(function () {
						goldPop.alpha -= 0.05;
						goldPop.y -= 1;
						if (goldPop.alpha <= 0) {
							goldPop.destroy();
							LK.clearInterval(fadeInterval);
						}
					}, 30);
					LK.getSound('zombieDeath').play();
					zombies[j].destroy();
					zombies.splice(j, 1);
					zombiesKilled++;
				}
				// Remove bullet
				bullets[i].destroy();
				bullets.splice(i, 1);
				break;
			}
		}
	}
	// Update zombies
	for (var k = zombies.length - 1; k >= 0; k--) {
		var result = zombies[k].update(tower);
		if (result === "gameover") {
			gameOver();
			return;
		}
	}
	// Update explosions
	for (var l = explosions.length - 1; l >= 0; l--) {
		if (explosions[l].update()) {
			explosions[l].destroy();
			explosions.splice(l, 1);
		}
	}
	// Update targets
	for (var m = targets.length - 1; m >= 0; m--) {
		if (targets[m].update()) {
			targets[m].destroy();
			targets.splice(m, 1);
		}
	}
	// Spawn zombies
	if (LK.ticks % waveInterval === 0 && zombiesInWave > 0) {
		spawnZombie();
	}
	// Check if wave is complete
	if (zombiesInWave <= 0 && zombies.length === 0) {
		// Start next wave after delay
		wave++;
		LK.setTimeout(function () {
			startWave();
		}, 3000);
		// Grant bonus gold between waves
		var bonus = 50 + wave * 10;
		gold += bonus;
		upgradePanel.updateGold(gold);
		// Show wave complete message
		var waveCompleteText = new Text2("WAVE " + (wave - 1) + " COMPLETE!", {
			size: 80,
			fill: 0x33ff33
		});
		waveCompleteText.x = CENTER_X;
		waveCompleteText.y = CENTER_Y;
		waveCompleteText.anchor.set(0.5);
		game.addChild(waveCompleteText);
		var bonusText = new Text2("BONUS: +" + bonus + " GOLD", {
			size: 60,
			fill: 0xffcc00
		});
		bonusText.x = CENTER_X;
		bonusText.y = CENTER_Y + 100;
		bonusText.anchor.set(0.5);
		game.addChild(bonusText);
		// Fade out text
		var fadeInterval = LK.setInterval(function () {
			waveCompleteText.alpha -= 0.02;
			bonusText.alpha -= 0.02;
			if (waveCompleteText.alpha <= 0) {
				waveCompleteText.destroy();
				bonusText.destroy();
				LK.clearInterval(fadeInterval);
			}
		}, 30);
	}
	// Update manual cooldown
	if (manualCooldown > 0) {
		manualCooldown--;
	}
});
// Start the game
startGame();

===================================================================
--- original.js
+++ change.js
@@ -96,9 +96,9 @@
 	healthBarContainer.addChild(healthBarFill);
 	healthBarContainer.y = -150;
 	self.addChild(healthBarContainer);
 	// Methods
-	self.update = function (zombies) {
+	self.update = function () {
 		// Decrease fire timer
 		if (self.fireTimer > 0) {
 			self.fireTimer--;
 		}
@@ -473,9 +473,9 @@
 // Game variables
 var tower;
 var upgradePanel;
 var bullets = [];
-var zombies = []; // Initialize zombies array to prevent undefined error
+var zombies = [];
 var explosions = [];
 var targets = [];
 var gold = 100;
 var wave = 1;
@@ -618,9 +618,9 @@
 	if (!isGameActive) {
 		return;
 	}
 	// Update tower
-	tower.update(zombies);
+	tower.update();
 	// Update upgrade panel
 	upgradePanel.update();
 	// Update bullets
 	for (var i = bullets.length - 1; i >= 0; i--) {