/**** 
* Plugins
****/ 
var tween = LK.import("@upit/tween.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;
		// Create trail particle
		if (Math.random() < 0.7) {
			var trailParticle = LK.getAsset('bullet', {
				anchorX: 0.5,
				anchorY: 0.5,
				scaleX: 0.3,
				scaleY: 0.3,
				tint: 0xFFFF88,
				alpha: 0.6
			});
			trailParticle.x = self.lastX;
			trailParticle.y = self.lastY;
			gameContainer.addChild(trailParticle);
			// Fade out trail particle
			tween(trailParticle, {
				alpha: 0,
				scaleX: 0.1,
				scaleY: 0.1
			}, {
				duration: 200,
				onFinish: function onFinish() {
					trailParticle.destroy();
				}
			});
		}
		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
		self.y += Math.sin(gameTime * 0.1 + self.bobOffset) * 0.5;
		self.rotation += 0.05;
	};
	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;
			}
			// Add pulsing effect based on distance to player
			var pulseIntensity = Math.max(0.1, 1 - distance / 500);
			var pulseSpeed = self.speed * 0.1;
			self.scaleX = 1 + Math.sin(gameTime * pulseSpeed) * pulseIntensity * 0.2;
			self.scaleY = 1 + Math.sin(gameTime * pulseSpeed) * pulseIntensity * 0.2;
			// Add red tint when close to player
			if (distance < 200) {
				self.tint = 0xFF6666;
			} else {
				self.tint = 0xFFFFFF;
			}
		}
	};
	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;
// 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);
// 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 grass ground covering
	var grassTileSize = 100;
	var grassTilesX = Math.ceil(mapWidth / grassTileSize);
	var grassTilesY = Math.ceil(mapHeight / grassTileSize);
	for (var gx = 0; gx < grassTilesX; gx++) {
		for (var gy = 0; gy < grassTilesY; gy++) {
			var grassTile = LK.getAsset('grass', {
				anchorX: 0,
				anchorY: 0
			});
			grassTile.x = gx * grassTileSize;
			grassTile.y = gy * grassTileSize;
			gameContainer.addChild(grassTile);
		}
	}
	// Create black barriers at map edges
	var mapBounds = [];
	var barrierThickness = 50;
	// Top barrier
	var topBarrier = LK.getAsset('barrier', {
		anchorX: 0,
		anchorY: 0,
		scaleX: mapWidth / 100,
		scaleY: barrierThickness / 100
	});
	topBarrier.x = 0;
	topBarrier.y = -barrierThickness;
	gameContainer.addChild(topBarrier);
	mapBounds.push(topBarrier);
	// Bottom barrier
	var bottomBarrier = LK.getAsset('barrier', {
		anchorX: 0,
		anchorY: 0,
		scaleX: mapWidth / 100,
		scaleY: barrierThickness / 100
	});
	bottomBarrier.x = 0;
	bottomBarrier.y = mapHeight;
	gameContainer.addChild(bottomBarrier);
	mapBounds.push(bottomBarrier);
	// Left barrier
	var leftBarrier = LK.getAsset('barrier', {
		anchorX: 0,
		anchorY: 0,
		scaleX: barrierThickness / 100,
		scaleY: mapHeight / 100
	});
	leftBarrier.x = -barrierThickness;
	leftBarrier.y = 0;
	gameContainer.addChild(leftBarrier);
	mapBounds.push(leftBarrier);
	// Right barrier
	var rightBarrier = LK.getAsset('barrier', {
		anchorX: 0,
		anchorY: 0,
		scaleX: barrierThickness / 100,
		scaleY: mapHeight / 100
	});
	rightBarrier.x = mapWidth;
	rightBarrier.y = 0;
	gameContainer.addChild(rightBarrier);
	mapBounds.push(rightBarrier);
	// Create map boundary indicators (grey inner boundaries)
	// 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;
	// 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;
	}
	// Add spawn effect - start small and grow
	zombie.scaleX = 0.1;
	zombie.scaleY = 0.1;
	zombie.alpha = 0.3;
	// Create spawn particles
	for (var sp = 0; sp < 6; sp++) {
		var spawnParticle = LK.getAsset('zombie', {
			anchorX: 0.5,
			anchorY: 0.5,
			scaleX: 0.2,
			scaleY: 0.2,
			tint: 0x00FF00,
			alpha: 0.8
		});
		spawnParticle.x = zombie.x;
		spawnParticle.y = zombie.y;
		var angle = sp / 6 * Math.PI * 2;
		spawnParticle.velocityX = Math.cos(angle) * 3;
		spawnParticle.velocityY = Math.sin(angle) * 3;
		gameContainer.addChild(spawnParticle);
		// Animate spawn particles
		tween(spawnParticle, {
			alpha: 0,
			scaleX: 0.05,
			scaleY: 0.05,
			x: spawnParticle.x + spawnParticle.velocityX * 20,
			y: spawnParticle.y + spawnParticle.velocityY * 20
		}, {
			duration: 400,
			onFinish: function onFinish() {
				spawnParticle.destroy();
			}
		});
	}
	// Animate zombie growth
	tween(zombie, {
		scaleX: 1,
		scaleY: 1,
		alpha: 1
	}, {
		duration: 500
	});
	zombies.push(zombie);
	gameContainer.addChild(zombie);
}
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;
	}
	// Create muzzle flash effect
	var muzzleFlash = LK.getAsset('bullet', {
		anchorX: 0.5,
		anchorY: 0.5,
		scaleX: 3,
		scaleY: 3,
		tint: 0xFFFF00,
		alpha: 0.8
	});
	muzzleFlash.x = player.x + 25; // Position at weapon location
	muzzleFlash.y = player.y;
	gameContainer.addChild(muzzleFlash);
	// Animate muzzle flash fade out
	tween(muzzleFlash, {
		alpha: 0,
		scaleX: 0.5,
		scaleY: 0.5
	}, {
		duration: 100,
		onFinish: function onFinish() {
			muzzleFlash.destroy();
		}
	});
	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') {
		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;
	}
	// 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 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 = 1.5;
						comboTxt.scaleY = 1.5;
						// Animate combo text
						tween(comboTxt, {
							scaleX: 1,
							scaleY: 1,
							alpha: 0.7
						}, {
							duration: 300
						});
					}
					// Create explosion effect at zombie position
					var explosionParticles = [];
					for (var p = 0; p < 8; p++) {
						var particle = LK.getAsset('bullet', {
							anchorX: 0.5,
							anchorY: 0.5,
							scaleX: 0.5,
							scaleY: 0.5,
							tint: 0xFF4444
						});
						particle.x = zombie.x;
						particle.y = zombie.y;
						var angle = p / 8 * Math.PI * 2;
						particle.velocityX = Math.cos(angle) * 8;
						particle.velocityY = Math.sin(angle) * 8;
						particle.life = 30;
						explosionParticles.push(particle);
						gameContainer.addChild(particle);
					}
					// Animate explosion particles
					var _animateExplosion = function animateExplosion() {
						for (var ep = explosionParticles.length - 1; ep >= 0; ep--) {
							var particle = explosionParticles[ep];
							particle.x += particle.velocityX;
							particle.y += particle.velocityY;
							particle.velocityX *= 0.9;
							particle.velocityY *= 0.9;
							particle.alpha = particle.life / 30;
							particle.life--;
							if (particle.life <= 0) {
								particle.destroy();
								explosionParticles.splice(ep, 1);
							}
						}
						if (explosionParticles.length > 0) {
							LK.setTimeout(_animateExplosion, 16);
						}
					};
					_animateExplosion();
					zombie.destroy();
					zombies.splice(j, 1);
					zombiesKilled++;
					LK.setScore(LK.getScore() + 10 * scoreMultiplier + Math.floor(gameTime / 60));
					scoreTxt.setText('Score: ' + LK.getScore());
					// Flash effect
					LK.effects.flashObject(zombie, 0xFF0000, 200);
				} else {
					// Zombie damaged but not destroyed
					LK.effects.flashObject(zombie, 0xFFAAAA, 100);
				}
				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;
			}
			// Show power-up collection effect
			LK.effects.flashObject(powerUp, 0xFFFF00, 200);
			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
			// Add screen shake effect
			var shakeIntensity = 20;
			var shakeDuration = 60;
			var shakeFrames = 0;
			var originalX = game.x;
			var originalY = game.y;
			var _shakeEffect = function shakeEffect() {
				if (shakeFrames < shakeDuration) {
					game.x = originalX + (Math.random() - 0.5) * shakeIntensity;
					game.y = originalY + (Math.random() - 0.5) * shakeIntensity;
					shakeFrames++;
					LK.setTimeout(_shakeEffect, 16);
				} else {
					game.x = originalX;
					game.y = originalY;
				}
			};
			_shakeEffect();
			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;
			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
@@ -285,10 +285,71 @@
 	// Initialize player
 	player = gameContainer.addChild(new Player());
 	player.x = mapWidth / 2;
 	player.y = mapHeight / 2;
-	// Create map boundary indicators
+	// Create grass ground covering
+	var grassTileSize = 100;
+	var grassTilesX = Math.ceil(mapWidth / grassTileSize);
+	var grassTilesY = Math.ceil(mapHeight / grassTileSize);
+	for (var gx = 0; gx < grassTilesX; gx++) {
+		for (var gy = 0; gy < grassTilesY; gy++) {
+			var grassTile = LK.getAsset('grass', {
+				anchorX: 0,
+				anchorY: 0
+			});
+			grassTile.x = gx * grassTileSize;
+			grassTile.y = gy * grassTileSize;
+			gameContainer.addChild(grassTile);
+		}
+	}
+	// Create black barriers at map edges
 	var mapBounds = [];
+	var barrierThickness = 50;
+	// Top barrier
+	var topBarrier = LK.getAsset('barrier', {
+		anchorX: 0,
+		anchorY: 0,
+		scaleX: mapWidth / 100,
+		scaleY: barrierThickness / 100
+	});
+	topBarrier.x = 0;
+	topBarrier.y = -barrierThickness;
+	gameContainer.addChild(topBarrier);
+	mapBounds.push(topBarrier);
+	// Bottom barrier
+	var bottomBarrier = LK.getAsset('barrier', {
+		anchorX: 0,
+		anchorY: 0,
+		scaleX: mapWidth / 100,
+		scaleY: barrierThickness / 100
+	});
+	bottomBarrier.x = 0;
+	bottomBarrier.y = mapHeight;
+	gameContainer.addChild(bottomBarrier);
+	mapBounds.push(bottomBarrier);
+	// Left barrier
+	var leftBarrier = LK.getAsset('barrier', {
+		anchorX: 0,
+		anchorY: 0,
+		scaleX: barrierThickness / 100,
+		scaleY: mapHeight / 100
+	});
+	leftBarrier.x = -barrierThickness;
+	leftBarrier.y = 0;
+	gameContainer.addChild(leftBarrier);
+	mapBounds.push(leftBarrier);
+	// Right barrier
+	var rightBarrier = LK.getAsset('barrier', {
+		anchorX: 0,
+		anchorY: 0,
+		scaleX: barrierThickness / 100,
+		scaleY: mapHeight / 100
+	});
+	rightBarrier.x = mapWidth;
+	rightBarrier.y = 0;
+	gameContainer.addChild(rightBarrier);
+	mapBounds.push(rightBarrier);
+	// Create map boundary indicators (grey inner boundaries)
 	// Top boundary
 	var topBound = LK.getAsset('bullet', {
 		anchorX: 0,
 		anchorY: 0,