/**** 
* Plugins
****/ 
var tween = LK.import("@upit/tween.v1");
var storage = LK.import("@upit/storage.v1");

/**** 
* Classes
****/ 
var Bullet = Container.expand(function () {
	var self = Container.call(this);
	var bulletGraphics = self.attachAsset('bullet', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = 12;
	self.directionX = 0;
	self.directionY = 0;
	self.update = function () {
		// Store previous position for trail effect
		if (self.lastX === undefined) {
			self.lastX = self.x;
			self.lastY = self.y;
		}
		self.x += self.directionX * self.speed;
		self.y += self.directionY * self.speed;
		// Trail particles removed
		self.lastX = self.x;
		self.lastY = self.y;
	};
	return self;
});
var Player = Container.expand(function () {
	var self = Container.call(this);
	var playerGraphics = self.attachAsset('player', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	// Add weapon to player
	var weaponGraphics = self.attachAsset('bullet', {
		anchorX: 0.5,
		anchorY: 0.5,
		scaleX: 1.5,
		scaleY: 1.5
	});
	weaponGraphics.x = 25; // Position weapon to the right of player
	weaponGraphics.y = 0;
	self.speed = 4;
	self.health = 1;
	self.lastShootTime = 0;
	self.shootInterval = 500; // milliseconds
	return self;
});
var PowerUp = Container.expand(function () {
	var self = Container.call(this);
	var powerUpGraphics = self.attachAsset('bullet', {
		anchorX: 0.5,
		anchorY: 0.5,
		scaleX: 2,
		scaleY: 2,
		tint: 0x00FF00
	});
	self.type = 'speed'; // 'speed', 'damage', 'fireRate'
	self.duration = 600; // 10 seconds at 60fps
	self.bobOffset = Math.random() * Math.PI * 2;
	self.update = function () {
		// Bobbing animation removed
	};
	return self;
});
var Shop = Container.expand(function () {
	var self = Container.call(this);
	// Shop building graphics
	var shopGraphics = self.attachAsset('zombie', {
		anchorX: 0.5,
		anchorY: 0.5,
		scaleX: 2,
		scaleY: 2,
		tint: 0x8B4513
	});
	// Shop sign
	var shopSign = self.attachAsset('bullet', {
		anchorX: 0.5,
		anchorY: 0.5,
		scaleX: 3,
		scaleY: 1,
		tint: 0xFFFFFF
	});
	shopSign.y = -200;
	self.addChild(shopSign);
	self.isPlayerNear = false;
	self.lastPlayerNear = false;
	self.update = function () {
		if (player) {
			var dx = player.x - self.x;
			var dy = player.y - self.y;
			var distance = Math.sqrt(dx * dx + dy * dy);
			self.isPlayerNear = distance < 200;
			// Check if player just entered shop range
			if (!self.lastPlayerNear && self.isPlayerNear) {
				showShopUI();
			}
			// Check if player just left shop range
			else if (self.lastPlayerNear && !self.isPlayerNear) {
				hideShopUI();
			}
			self.lastPlayerNear = self.isPlayerNear;
		}
	};
	return self;
});
var Zombie = Container.expand(function () {
	var self = Container.call(this);
	var zombieGraphics = self.attachAsset('zombie', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = 2;
	self.health = 1;
	self.maxHealth = 1;
	// Create health bar background
	var healthBarBg = LK.getAsset('bullet', {
		anchorX: 0.5,
		anchorY: 0.5,
		scaleX: 3,
		scaleY: 0.5,
		tint: 0x333333
	});
	healthBarBg.y = -140;
	self.addChild(healthBarBg);
	// Create health bar fill
	var healthBarFill = LK.getAsset('bullet', {
		anchorX: 0.5,
		anchorY: 0.5,
		scaleX: 3,
		scaleY: 0.5,
		tint: 0xFF0000
	});
	healthBarFill.y = -140;
	self.addChild(healthBarFill);
	self.healthBarFill = healthBarFill;
	self.update = function () {
		if (player) {
			var dx = player.x - self.x;
			var dy = player.y - self.y;
			var distance = Math.sqrt(dx * dx + dy * dy);
			if (distance > 0) {
				self.x += dx / distance * self.speed;
				self.y += dy / distance * self.speed;
			}
			// Pulsing and tint effects removed
		}
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x2E2E2E
});

/**** 
* Game Code
****/ 
// Game state management
var gameState = 'menu'; // 'menu', 'playing', 'gameOver'
var menuContainer;
var playButton;
// Game variables
var player;
var zombies = [];
var bullets = [];
var powerUps = [];
var dragNode = null;
var gameTime = 0;
var zombieSpawnRate = 50; // frames between spawns
var zombieSpeed = 4;
var zombiesKilled = 0;
var waveNumber = 1;
var comboCount = 0;
var comboTimer = 0;
var comboDecayTime = 180; // 3 seconds at 60fps
var scoreMultiplier = 1;
var playerFireRate = 60; // frames between shots
var playerDamage = 1;
var playerSpeed = 4;
// Map system variables
var mapWidth = 6144; // 3x wider than screen
var mapHeight = 8196; // 3x taller than screen
var cameraOffsetX = 0;
var cameraOffsetY = 0;
var gameContainer;
// Minimap variables
var minimap;
var minimapContainer;
var minimapPlayer;
var minimapZombies = [];
var minimapSize = 200;
var minimapScale = minimapSize / Math.max(mapWidth, mapHeight);
// Shop variables
var shop;
var shopUI;
var shopVisible = false;
var coins = storage.coins || 0;
var shopUpgrades = {
	damage: storage.damageUpgrade || 0,
	speed: storage.speedUpgrade || 0,
	fireRate: storage.fireRateUpgrade || 0
};
// Shop UI elements
var shopContainer;
var coinsTxt;
var shopTitle;
var upgradeButtons = [];
// Create game container for camera system
gameContainer = new Container();
game.addChild(gameContainer);
// Create main menu
menuContainer = new Container();
game.addChild(menuContainer);
// Menu title
var titleTxt = new Text2('ZOMBIE SHOOTER', {
	size: 120,
	fill: 0xFF4444
});
titleTxt.anchor.set(0.5, 0.5);
titleTxt.x = 2048 / 2;
titleTxt.y = 2732 / 2 - 200;
menuContainer.addChild(titleTxt);
// Play button background
var playButtonBg = LK.getAsset('zombie', {
	anchorX: 0.5,
	anchorY: 0.5,
	scaleX: 1.5,
	scaleY: 0.8,
	tint: 0x44AA44
});
playButtonBg.x = 2048 / 2;
playButtonBg.y = 2732 / 2 + 50;
menuContainer.addChild(playButtonBg);
// Play button text
var playButtonTxt = new Text2('PLAY', {
	size: 80,
	fill: 0xFFFFFF
});
playButtonTxt.anchor.set(0.5, 0.5);
playButtonTxt.x = 2048 / 2;
playButtonTxt.y = 2732 / 2 + 50;
menuContainer.addChild(playButtonTxt);
// Store reference to play button for event handling
playButton = playButtonBg;
// Make sure menu is visible at start
menuContainer.visible = true;
gameState = 'menu';
// Game UI Elements (initially hidden)
var scoreTxt = new Text2('Score: 0', {
	size: 60,
	fill: 0xFFFFFF
});
scoreTxt.anchor.set(0.5, 0);
scoreTxt.visible = false;
LK.gui.top.addChild(scoreTxt);
var waveTxt = new Text2('Wave: 1', {
	size: 50,
	fill: 0xFFFFFF
});
waveTxt.anchor.set(0, 0);
waveTxt.x = 120;
waveTxt.y = 20;
waveTxt.visible = false;
LK.gui.top.addChild(waveTxt);
var timeTxt = new Text2('Time: 0s', {
	size: 50,
	fill: 0xFFFFFF
});
timeTxt.anchor.set(1, 0);
timeTxt.x = -20;
timeTxt.y = 20;
timeTxt.visible = false;
LK.gui.topRight.addChild(timeTxt);
var comboTxt = new Text2('', {
	size: 80,
	fill: 0xFFAA00
});
comboTxt.anchor.set(0.5, 0.5);
comboTxt.visible = false;
LK.gui.center.addChild(comboTxt);
// Coins display
coinsTxt = new Text2('Coins: ' + coins, {
	size: 50,
	fill: 0xFFD700
});
coinsTxt.anchor.set(0, 0);
coinsTxt.x = 120;
coinsTxt.y = 80;
coinsTxt.visible = false;
LK.gui.top.addChild(coinsTxt);
// Shop UI creation
function createShopUI() {
	// Clear existing shop container if it exists
	if (shopContainer) {
		shopContainer.destroy();
	}
	// Reset upgrade buttons array
	upgradeButtons = [];
	shopContainer = new Container();
	// Shop background
	var shopBg = LK.getAsset('zombie', {
		anchorX: 0.5,
		anchorY: 0.5,
		scaleX: 8,
		scaleY: 6,
		tint: 0x2A2A2A,
		alpha: 0.9
	});
	shopBg.x = 2048 / 2;
	shopBg.y = 2732 / 2;
	shopContainer.addChild(shopBg);
	// Shop title
	shopTitle = new Text2('SHOP', {
		size: 150,
		fill: 0xFFFFFF
	});
	shopTitle.anchor.set(0.5, 0.5);
	shopTitle.x = 2048 / 2;
	shopTitle.y = 2732 / 2 - 400;
	shopContainer.addChild(shopTitle);
	// Coins display in shop
	var shopCoinsTxt = new Text2('Coins: ' + coins, {
		size: 80,
		fill: 0xFFD700
	});
	shopCoinsTxt.anchor.set(0.5, 0.5);
	shopCoinsTxt.x = 2048 / 2;
	shopCoinsTxt.y = 2732 / 2 - 300;
	shopContainer.addChild(shopCoinsTxt);
	// Create upgrade buttons
	var upgradeTypes = [{
		name: 'Damage +1',
		type: 'damage',
		cost: 100,
		y: -150
	}, {
		name: 'Speed +1',
		type: 'speed',
		cost: 150,
		y: -50
	}, {
		name: 'Fire Rate +1',
		type: 'fireRate',
		cost: 200,
		y: 50
	}];
	for (var i = 0; i < upgradeTypes.length; i++) {
		var upgrade = upgradeTypes[i];
		var currentLevel = shopUpgrades[upgrade.type];
		var cost = upgrade.cost + currentLevel * 50;
		// Button background
		var buttonBg = LK.getAsset('bullet', {
			anchorX: 0.5,
			anchorY: 0.5,
			scaleX: 20,
			scaleY: 4,
			tint: coins >= cost ? 0x44AA44 : 0xAA4444
		});
		buttonBg.x = 2048 / 2;
		buttonBg.y = 2732 / 2 + upgrade.y;
		shopContainer.addChild(buttonBg);
		// Button text
		var buttonTxt = new Text2(upgrade.name + ' (Lv.' + currentLevel + ') - ' + cost + ' coins', {
			size: 70,
			fill: 0xFFFFFF
		});
		buttonTxt.anchor.set(0.5, 0.5);
		buttonTxt.x = 2048 / 2;
		buttonTxt.y = 2732 / 2 + upgrade.y;
		shopContainer.addChild(buttonTxt);
		upgradeButtons.push({
			bg: buttonBg,
			txt: buttonTxt,
			type: upgrade.type,
			cost: cost
		});
	}
	// Close button
	var closeBtn = LK.getAsset('bullet', {
		anchorX: 0.5,
		anchorY: 0.5,
		scaleX: 8,
		scaleY: 2,
		tint: 0xAA4444
	});
	closeBtn.x = 2048 / 2;
	closeBtn.y = 2732 / 2 + 200;
	shopContainer.addChild(closeBtn);
	var closeTxt = new Text2('CLOSE', {
		size: 80,
		fill: 0xFFFFFF
	});
	closeTxt.anchor.set(0.5, 0.5);
	closeTxt.x = 2048 / 2;
	closeTxt.y = 2732 / 2 + 200;
	shopContainer.addChild(closeTxt);
	upgradeButtons.push({
		bg: closeBtn,
		txt: closeTxt,
		type: 'close',
		cost: 0
	});
	shopContainer.visible = false;
	game.addChild(shopContainer);
}
function showShopUI() {
	if (!shopContainer) {
		createShopUI();
	}
	shopContainer.visible = true;
	shopVisible = true;
}
function hideShopUI() {
	if (shopContainer) {
		shopContainer.visible = false;
	}
	shopVisible = false;
}
function purchaseUpgrade(type) {
	var currentLevel = shopUpgrades[type];
	var baseCost = type === 'damage' ? 100 : type === 'speed' ? 150 : 200;
	var cost = baseCost + currentLevel * 50;
	if (coins >= cost) {
		coins -= cost;
		shopUpgrades[type]++;
		// Save to storage
		storage.coins = coins;
		storage[type + 'Upgrade'] = shopUpgrades[type];
		// Update UI
		coinsTxt.setText('Coins: ' + coins);
		// Apply upgrade immediately
		applyUpgrades();
		// Refresh shop UI
		hideShopUI();
		showShopUI();
		return true;
	}
	return false;
}
function applyUpgrades() {
	// Apply damage upgrade
	playerDamage = 1 + shopUpgrades.damage;
	// Apply speed upgrade
	if (player) {
		player.speed = 4 + shopUpgrades.speed;
	}
	// Apply fire rate upgrade
	playerFireRate = Math.max(20, 60 - shopUpgrades.fireRate * 10);
}
// Game initialization function
function initializeGame() {
	// Reset game variables
	gameTime = 0;
	zombiesKilled = 0;
	waveNumber = 1;
	comboCount = 0;
	comboTimer = 0;
	scoreMultiplier = 1;
	zombieSpawnRate = 50;
	zombieSpeed = 4;
	// Clear existing game objects
	if (player) {
		player.destroy();
	}
	for (var i = 0; i < zombies.length; i++) {
		zombies[i].destroy();
	}
	for (var j = 0; j < bullets.length; j++) {
		bullets[j].destroy();
	}
	zombies = [];
	bullets = [];
	// Initialize player
	player = gameContainer.addChild(new Player());
	player.x = mapWidth / 2;
	player.y = mapHeight / 2;
	// Create map boundary indicators
	var mapBounds = [];
	// Top boundary
	var topBound = LK.getAsset('bullet', {
		anchorX: 0,
		anchorY: 0,
		scaleX: mapWidth / 16,
		scaleY: 2,
		tint: 0x444444
	});
	topBound.x = 0;
	topBound.y = 0;
	gameContainer.addChild(topBound);
	mapBounds.push(topBound);
	// Bottom boundary
	var bottomBound = LK.getAsset('bullet', {
		anchorX: 0,
		anchorY: 0,
		scaleX: mapWidth / 16,
		scaleY: 2,
		tint: 0x444444
	});
	bottomBound.x = 0;
	bottomBound.y = mapHeight - 32;
	gameContainer.addChild(bottomBound);
	mapBounds.push(bottomBound);
	// Left boundary
	var leftBound = LK.getAsset('bullet', {
		anchorX: 0,
		anchorY: 0,
		scaleX: 2,
		scaleY: mapHeight / 16,
		tint: 0x444444
	});
	leftBound.x = 0;
	leftBound.y = 0;
	gameContainer.addChild(leftBound);
	mapBounds.push(leftBound);
	// Right boundary
	var rightBound = LK.getAsset('bullet', {
		anchorX: 0,
		anchorY: 0,
		scaleX: 2,
		scaleY: mapHeight / 16,
		tint: 0x444444
	});
	rightBound.x = mapWidth - 32;
	rightBound.y = 0;
	gameContainer.addChild(rightBound);
	mapBounds.push(rightBound);
	// Reset camera position
	cameraOffsetX = 0;
	cameraOffsetY = 0;
	// Reset score
	LK.setScore(0);
	scoreTxt.setText('Score: 0');
	// Show game UI
	scoreTxt.visible = true;
	waveTxt.visible = true;
	timeTxt.visible = true;
	comboTxt.visible = true;
	coinsTxt.visible = true;
	// Create and position shop
	shop = gameContainer.addChild(new Shop());
	shop.x = mapWidth / 4; // Place shop in the left quarter of the map
	shop.y = mapHeight / 4;
	// Apply purchased upgrades
	applyUpgrades();
	// Update coins display
	coinsTxt.setText('Coins: ' + coins);
	// Create minimap
	minimapContainer = new Container();
	minimap = LK.getAsset('bullet', {
		anchorX: 0,
		anchorY: 0,
		scaleX: minimapSize / 16,
		scaleY: minimapSize / 16,
		tint: 0x333333,
		alpha: 0.8
	});
	minimap.x = 0;
	minimap.y = 0;
	minimapContainer.addChild(minimap);
	// Create minimap player indicator
	minimapPlayer = LK.getAsset('bullet', {
		anchorX: 0.5,
		anchorY: 0.5,
		scaleX: 0.8,
		scaleY: 0.8,
		tint: 0x00FF00
	});
	minimapContainer.addChild(minimapPlayer);
	// Position minimap in bottom right
	minimapContainer.x = -minimapSize - 20;
	minimapContainer.y = -minimapSize - 20;
	LK.gui.bottomRight.addChild(minimapContainer);
	// Clear existing minimap zombies
	minimapZombies = [];
	// Show minimap
	if (minimapContainer) {
		minimapContainer.visible = true;
	}
	// Hide menu
	menuContainer.visible = false;
	// Set game state
	gameState = 'playing';
}
// Don't initialize player immediately - wait for menu interaction
// Helper functions
function spawnZombie() {
	var zombie = new Zombie();
	var side = Math.floor(Math.random() * 4);
	switch (side) {
		case 0:
			// top
			zombie.x = Math.random() * mapWidth;
			zombie.y = -50;
			break;
		case 1:
			// right
			zombie.x = mapWidth + 50;
			zombie.y = Math.random() * mapHeight;
			break;
		case 2:
			// bottom
			zombie.x = Math.random() * mapWidth;
			zombie.y = mapHeight + 50;
			break;
		case 3:
			// left
			zombie.x = -50;
			zombie.y = Math.random() * mapHeight;
			break;
	}
	// Create different zombie types based on level
	var zombieType = Math.random();
	if (waveNumber >= 3 && zombieType < 0.3) {
		// Fast zombie
		zombie.speed = zombieSpeed * 1.8;
		zombie.health = 1;
		zombie.maxHealth = 1;
		zombie.tint = 0xFF8888;
		zombie.scaleX = 0.8;
		zombie.scaleY = 0.8;
	} else if (waveNumber >= 5 && zombieType < 0.5) {
		// Tank zombie
		zombie.speed = zombieSpeed * 0.6;
		zombie.health = 3;
		zombie.maxHealth = 3;
		zombie.tint = 0x888888;
		zombie.scaleX = 1.3;
		zombie.scaleY = 1.3;
	} else {
		// Normal zombie
		zombie.speed = zombieSpeed;
		zombie.health = 1;
		zombie.maxHealth = 1;
	}
	// Spawn effects removed
	zombies.push(zombie);
	gameContainer.addChild(zombie);
	// Add zombie to minimap
	if (minimapContainer) {
		var minimapZombie = LK.getAsset('bullet', {
			anchorX: 0.5,
			anchorY: 0.5,
			scaleX: 0.4,
			scaleY: 0.4,
			tint: 0xFF4444
		});
		minimapZombie.x = zombie.x * minimapScale;
		minimapZombie.y = zombie.y * minimapScale;
		minimapContainer.addChild(minimapZombie);
		minimapZombies.push(minimapZombie);
		zombie.minimapRef = minimapZombie;
	}
}
function findNearestZombie() {
	var nearestZombie = null;
	var nearestDistance = Infinity;
	for (var i = 0; i < zombies.length; i++) {
		var zombie = zombies[i];
		var dx = zombie.x - player.x;
		var dy = zombie.y - player.y;
		var distance = Math.sqrt(dx * dx + dy * dy);
		if (distance < nearestDistance) {
			nearestDistance = distance;
			nearestZombie = zombie;
		}
	}
	return nearestZombie;
}
function shootBullet() {
	var target = findNearestZombie();
	if (!target) return;
	var bullet = new Bullet();
	bullet.x = player.x;
	bullet.y = player.y;
	// Calculate zombie's movement direction
	var zombieDx = player.x - target.x;
	var zombieDy = player.y - target.y;
	var zombieDistance = Math.sqrt(zombieDx * zombieDx + zombieDy * zombieDy);
	var zombieDirectionX = zombieDistance > 0 ? zombieDx / zombieDistance : 0;
	var zombieDirectionY = zombieDistance > 0 ? zombieDy / zombieDistance : 0;
	// Predict where zombie will be
	var timeToTarget = zombieDistance / bullet.speed;
	var predictedX = target.x + zombieDirectionX * target.speed * timeToTarget;
	var predictedY = target.y + zombieDirectionY * target.speed * timeToTarget;
	// Aim at predicted position
	var dx = predictedX - player.x;
	var dy = predictedY - player.y;
	var distance = Math.sqrt(dx * dx + dy * dy);
	if (distance > 0) {
		bullet.directionX = dx / distance;
		bullet.directionY = dy / distance;
	}
	// Muzzle flash effect removed
	bullets.push(bullet);
	gameContainer.addChild(bullet);
	LK.getSound('shoot').play();
}
function updateDifficulty() {
	waveNumber = Math.floor(gameTime / 1200) + 1; // New wave every 20 seconds
	zombieSpawnRate = Math.max(15, 50 - waveNumber * 8);
	zombieSpeed = 4 + (waveNumber - 1) * 1.2;
	waveTxt.setText('Wave: ' + waveNumber);
}
// Event handlers
function handleMove(x, y, obj) {
	if (dragNode) {
		// Convert screen coordinates to world coordinates
		var worldX = x - cameraOffsetX;
		var worldY = y - cameraOffsetY;
		// Keep player within map bounds
		dragNode.x = Math.max(75, Math.min(mapWidth - 75, worldX));
		dragNode.y = Math.max(75, Math.min(mapHeight - 75, worldY));
	}
}
game.move = handleMove;
game.down = function (x, y, obj) {
	if (gameState === 'menu') {
		// Check if play button was clicked
		var buttonBounds = playButton.getBounds();
		var buttonCenterX = playButton.x;
		var buttonCenterY = playButton.y;
		var buttonWidth = buttonBounds.width;
		var buttonHeight = buttonBounds.height;
		// Simple bounds check
		if (x >= buttonCenterX - buttonWidth / 2 && x <= buttonCenterX + buttonWidth / 2 && y >= buttonCenterY - buttonHeight / 2 && y <= buttonCenterY + buttonHeight / 2) {
			initializeGame();
		}
	} else if (gameState === 'playing') {
		// Check if shop UI is visible and handle shop clicks
		if (shopVisible && shopContainer && shopContainer.visible) {
			// Check upgrade button clicks
			for (var i = 0; i < upgradeButtons.length; i++) {
				var button = upgradeButtons[i];
				var buttonCenterX = button.bg.x;
				var buttonCenterY = button.bg.y;
				var buttonWidth = button.bg.width;
				var buttonHeight = button.bg.height;
				if (x >= buttonCenterX - buttonWidth / 2 && x <= buttonCenterX + buttonWidth / 2 && y >= buttonCenterY - buttonHeight / 2 && y <= buttonCenterY + buttonHeight / 2) {
					if (button.type === 'close') {
						hideShopUI();
					} else {
						purchaseUpgrade(button.type);
					}
					return;
				}
			}
		} else {
			// Normal gameplay - allow player movement
			dragNode = player;
			handleMove(x, y, obj);
		}
	}
};
game.up = function (x, y, obj) {
	dragNode = null;
};
// Main game loop
game.update = function () {
	// Only update game logic when playing
	if (gameState !== 'playing') {
		return;
	}
	gameTime++;
	// Update UI
	timeTxt.setText('Time: ' + Math.floor(gameTime / 60) + 's');
	// Update combo system
	if (comboTimer > 0) {
		comboTimer--;
		if (comboTimer <= 0) {
			comboCount = 0;
			scoreMultiplier = 1;
			comboTxt.setText('');
		}
	}
	// Continuously increase difficulty based on score instead of waves
	var currentScore = LK.getScore();
	zombieSpawnRate = Math.max(10, 50 - Math.floor(currentScore / 100) * 2);
	zombieSpeed = 4 + Math.floor(currentScore / 200) * 0.5;
	waveNumber = Math.floor(currentScore / 500) + 1;
	waveTxt.setText('Level: ' + waveNumber);
	// Spawn zombies with dynamic frequency based on score
	if (gameTime % zombieSpawnRate === 0) {
		spawnZombie();
		// Spawn additional zombies based on current level
		var additionalSpawns = Math.floor(waveNumber / 2);
		for (var spawn = 0; spawn < additionalSpawns; spawn++) {
			if (gameTime % (zombieSpawnRate * (spawn + 2)) === 0) {
				spawnZombie();
			}
		}
	}
	// Update camera to follow player
	if (player) {
		var targetCameraX = -(player.x - 2048 / 2);
		var targetCameraY = -(player.y - 2732 / 2);
		// Smooth camera movement
		cameraOffsetX += (targetCameraX - cameraOffsetX) * 0.1;
		cameraOffsetY += (targetCameraY - cameraOffsetY) * 0.1;
		// Keep camera within map bounds
		cameraOffsetX = Math.max(-(mapWidth - 2048), Math.min(0, cameraOffsetX));
		cameraOffsetY = Math.max(-(mapHeight - 2732), Math.min(0, cameraOffsetY));
		// Apply camera offset to game container
		gameContainer.x = cameraOffsetX;
		gameContainer.y = cameraOffsetY;
		// Update minimap player position
		if (minimapPlayer) {
			minimapPlayer.x = player.x * minimapScale;
			minimapPlayer.y = player.y * minimapScale;
		}
	}
	// Spawn power-ups occasionally
	if (gameTime % 1800 === 0) {
		// Every 30 seconds
		var powerUp = new PowerUp();
		powerUp.x = Math.random() * (mapWidth - 200) + 100;
		powerUp.y = Math.random() * (mapHeight - 200) + 100;
		var powerTypes = ['speed', 'damage', 'fireRate'];
		powerUp.type = powerTypes[Math.floor(Math.random() * powerTypes.length)];
		switch (powerUp.type) {
			case 'speed':
				powerUp.tint = 0x00FF00;
				break;
			case 'damage':
				powerUp.tint = 0xFF0000;
				break;
			case 'fireRate':
				powerUp.tint = 0x0000FF;
				break;
		}
		powerUps.push(powerUp);
		gameContainer.addChild(powerUp);
	}
	// Auto-shoot with dynamic fire rate
	if (gameTime % playerFireRate === 0) {
		shootBullet();
	}
	// Update minimap zombie positions
	for (var mz = 0; mz < zombies.length; mz++) {
		var zombie = zombies[mz];
		if (zombie.minimapRef) {
			zombie.minimapRef.x = zombie.x * minimapScale;
			zombie.minimapRef.y = zombie.y * minimapScale;
		}
	}
	// Update bullets
	for (var i = bullets.length - 1; i >= 0; i--) {
		var bullet = bullets[i];
		// Remove bullets that are off screen (expanded map)
		if (bullet.x < -200 || bullet.x > mapWidth + 200 || bullet.y < -200 || bullet.y > mapHeight + 200) {
			bullet.destroy();
			bullets.splice(i, 1);
			continue;
		}
		// Check bullet-zombie collisions
		for (var j = zombies.length - 1; j >= 0; j--) {
			var zombie = zombies[j];
			if (bullet.intersects(zombie)) {
				// Zombie hit
				LK.getSound('zombieHit').play();
				zombie.health -= playerDamage;
				// Update health bar
				if (zombie.healthBarFill) {
					zombie.healthBarFill.scaleX = 3 * (zombie.health / zombie.maxHealth);
				}
				// Only destroy zombie if health reaches 0
				if (zombie.health <= 0) {
					// Update combo system
					comboCount++;
					comboTimer = comboDecayTime;
					scoreMultiplier = Math.min(5, 1 + Math.floor(comboCount / 3));
					// Show combo text
					if (comboCount > 2) {
						comboTxt.setText('COMBO x' + scoreMultiplier);
						comboTxt.alpha = 1;
						comboTxt.scaleX = 1;
						comboTxt.scaleY = 1;
						// Combo text animation removed
					}
					// Explosion particles removed
					// Clean up minimap reference
					if (zombie.minimapRef) {
						zombie.minimapRef.destroy();
						var minimapIndex = minimapZombies.indexOf(zombie.minimapRef);
						if (minimapIndex !== -1) {
							minimapZombies.splice(minimapIndex, 1);
						}
					}
					zombie.destroy();
					zombies.splice(j, 1);
					zombiesKilled++;
					LK.setScore(LK.getScore() + 10 * scoreMultiplier + Math.floor(gameTime / 60));
					scoreTxt.setText('Score: ' + LK.getScore());
					// Award coins for killing zombies
					var coinsAwarded = 5 + Math.floor(waveNumber / 2);
					coins += coinsAwarded;
					storage.coins = coins;
					coinsTxt.setText('Coins: ' + coins);
					// Flash effects removed
				} else {
					// Zombie damaged but not destroyed
					// Flash effects removed
				}
				bullet.destroy();
				bullets.splice(i, 1);
				break;
			}
		}
	}
	// Check power-up collection
	for (var p = powerUps.length - 1; p >= 0; p--) {
		var powerUp = powerUps[p];
		if (player.intersects(powerUp)) {
			// Apply power-up effect
			switch (powerUp.type) {
				case 'speed':
					player.speed = Math.min(8, player.speed + 1);
					break;
				case 'damage':
					playerDamage += 1;
					break;
				case 'fireRate':
					playerFireRate = Math.max(20, playerFireRate - 10);
					break;
			}
			// Power-up collection effect removed
			powerUp.destroy();
			powerUps.splice(p, 1);
			LK.setScore(LK.getScore() + 50);
			scoreTxt.setText('Score: ' + LK.getScore());
		}
	}
	// Check player-zombie collisions
	for (var k = 0; k < zombies.length; k++) {
		var zombie = zombies[k];
		if (player.intersects(zombie)) {
			// Player hit - game over
			// Screen shake effect removed
			LK.effects.flashScreen(0xFF0000, 1000);
			// Reset to menu state
			gameState = 'menu';
			menuContainer.visible = true;
			scoreTxt.visible = false;
			waveTxt.visible = false;
			timeTxt.visible = false;
			comboTxt.visible = false;
			coinsTxt.visible = false;
			if (minimapContainer) {
				minimapContainer.visible = false;
			}
			if (shopContainer) {
				shopContainer.visible = false;
			}
			shopVisible = false;
			LK.showGameOver();
			return;
		}
	}
	// Remove zombies that are too far off screen (cleanup)
	for (var l = zombies.length - 1; l >= 0; l--) {
		var zombie = zombies[l];
		if (zombie.x < -400 || zombie.x > mapWidth + 400 || zombie.y < -400 || zombie.y > mapHeight + 400) {
			zombie.destroy();
			zombies.splice(l, 1);
		}
	}
};
// Start background music
LK.playMusic('bgmusic');

===================================================================
--- original.js
+++ change.js
@@ -747,12 +747,9 @@
 				if (x >= buttonCenterX - buttonWidth / 2 && x <= buttonCenterX + buttonWidth / 2 && y >= buttonCenterY - buttonHeight / 2 && y <= buttonCenterY + buttonHeight / 2) {
 					if (button.type === 'close') {
 						hideShopUI();
 					} else {
-						// Check if player has enough coins
-						if (coins >= button.cost) {
-							purchaseUpgrade(button.type);
-						}
+						purchaseUpgrade(button.type);
 					}
 					return;
 				}
 			}