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

/**** 
* Classes
****/ 
// Bullet class
var Bullet = Container.expand(function () {
	var self = Container.call(this);
	var bulletSprite = self.attachAsset('bullet', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.radius = bulletSprite.width / 2;
	self.vx = 0;
	self.vy = 0;
	self.lifetime = 60; // frames
	self.update = function () {
		self.x += self.vx;
		self.y += self.vy;
		self.lifetime--;
	};
	return self;
});
// Hero class
var Hero = Container.expand(function () {
	var self = Container.call(this);
	var heroSprite = self.attachAsset('hero', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.heroSprite = heroSprite;
	// Add gun sprite to hero's hand
	var gunSprite = self.attachAsset('gun', {
		anchorX: 0.2,
		// grip of gun
		anchorY: 0.5,
		width: heroSprite.width * 0.45,
		height: heroSprite.height * 0.22
	});
	gunSprite.x = heroSprite.width * 0.32; // offset to right hand
	gunSprite.y = 0;
	self.radius = heroSprite.width / 2;
	self.speed = 18; // pixels per move
	self.lastShotTick = 0;
	self.shootCooldown = 18; // frames between shots
	// Allow skin change
	self.setSkin = function (skinId) {
		if (!skinId || skinId === "hero") {
			// Already default
			return;
		}
		// Remove old sprite
		if (self.heroSprite && self.heroSprite.parent) {
			self.removeChild(self.heroSprite);
		}
		// Add new sprite
		var newSprite = self.attachAsset(skinId, {
			anchorX: 0.5,
			anchorY: 0.5,
			width: heroSprite.width,
			height: heroSprite.height
		});
		self.heroSprite = newSprite;
		// Move gun to top
		if (gunSprite && gunSprite.parent) {
			self.removeChild(gunSprite);
			self.addChild(gunSprite);
		}
		// Update radius
		self.radius = newSprite.width / 2;
	};
	self.update = function () {};
	return self;
});
// Powerup class
var Powerup = Container.expand(function () {
	var self = Container.call(this);
	var powerupSprite = self.attachAsset('powerup', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.radius = powerupSprite.width / 2;
	self.type = 'rapid'; // only one type for MVP
	self.update = function () {};
	return self;
});
// Zombie class
var Zombie = Container.expand(function () {
	var self = Container.call(this);
	// Default to normal zombie asset
	var zombieSprite = self.attachAsset('zombie', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.zombieSprite = zombieSprite;
	self.radius = zombieSprite.width / 2;
	self.baseSpeed = 3 + Math.random() * 2; // base speed, will be increased by wave
	self.speed = self.baseSpeed;
	self.target = null; // set to hero
	self.maxHp = 1;
	self.hp = 1;
	self.wave = 1;
	self.type = "normal"; // can be "normal", "fast", "tank", "crawler"
	self.setWave = function (wave) {
		self.wave = wave;
		// Remove old sprite if present
		if (self.zombieSprite && self.zombieSprite.parent) {
			self.removeChild(self.zombieSprite);
		}
		// Decide type
		var r = Math.random();
		if (wave >= 7 && r < 0.18) {
			// Crawler: slow, small, hard to hit
			self.type = "crawler";
			self.speed = 1.7 + 0.12 * wave;
			self.maxHp = 2 + Math.floor(wave / 3);
			self.hp = self.maxHp;
			self.zombieSprite = self.attachAsset('zombie_crawler', {
				anchorX: 0.5,
				anchorY: 0.5
			});
			self.radius = self.zombieSprite.width / 2;
			self.zombieSprite.tint = 0x8e8e8e; // grayish
		} else if (wave >= 6 && r < 0.38) {
			// Tank zombie: slow but high HP
			self.type = "tank";
			self.speed = 2 + 0.15 * wave;
			self.maxHp = 3 + Math.floor(wave / 2);
			self.hp = self.maxHp;
			self.zombieSprite = self.attachAsset('zombie_tank', {
				anchorX: 0.5,
				anchorY: 0.5
			});
			self.radius = self.zombieSprite.width / 2;
			self.zombieSprite.tint = 0x6e4e2e; // brownish
		} else if (wave >= 3 && r < 0.63) {
			// Fast zombie: high speed, low HP
			self.type = "fast";
			self.speed = 5 + 0.4 * wave;
			self.maxHp = 1;
			self.hp = 1;
			self.zombieSprite = self.attachAsset('zombie_fast', {
				anchorX: 0.5,
				anchorY: 0.5
			});
			self.radius = self.zombieSprite.width / 2;
			self.zombieSprite.tint = 0x7cf442; // bright green
		} else {
			// Normal zombie
			self.type = "normal";
			self.speed = self.baseSpeed + (wave - 1) * 0.5;
			self.maxHp = 1 + Math.floor(wave / 4);
			self.hp = self.maxHp;
			self.zombieSprite = self.attachAsset('zombie', {
				anchorX: 0.5,
				anchorY: 0.5
			});
			self.radius = self.zombieSprite.width / 2;
			self.zombieSprite.tint = 0x7bbf3f; // normal green
		}
	};
	// Health bar setup
	var healthBarW = zombieSprite.width * 0.7;
	var healthBarH = 16;
	var healthBarBg = LK.getAsset('hero', {
		anchorX: 0,
		anchorY: 0,
		width: healthBarW,
		height: healthBarH,
		color: 0x222222
	});
	healthBarBg.alpha = 0.7;
	var healthBarFill = LK.getAsset('hero', {
		anchorX: 0,
		anchorY: 0,
		width: healthBarW,
		height: healthBarH,
		color: 0x3FA34D
	});
	healthBarFill.alpha = 0.92;
	self.addChild(healthBarBg);
	self.addChild(healthBarFill);
	self.update = function () {
		if (!self.target) return;
		var dx = self.target.x - self.x;
		var dy = self.target.y - self.y;
		var dist = Math.sqrt(dx * dx + dy * dy);
		if (dist > 0) {
			self.x += self.speed * dx / dist;
			self.y += self.speed * dy / dist;
		}
		// Update health bar position and fill
		var barY = -self.radius - 30;
		healthBarBg.x = -healthBarW / 2;
		healthBarBg.y = barY;
		healthBarFill.x = -healthBarW / 2;
		healthBarFill.y = barY;
		var ratio = Math.max(0, Math.min(1, self.hp / self.maxHp));
		healthBarFill.width = healthBarW * ratio;
		if (ratio > 0.6) {
			healthBarFill.tint = 0x3FA34D;
		} else if (ratio > 0.3) {
			healthBarFill.tint = 0xF7E733;
		} else {
			healthBarFill.tint = 0xD83318;
		}
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x181818
});

/**** 
* Game Code
****/ 
// Game area
// Hero: red box
// Zombie: green ellipse
// Bullet: yellow box
// Powerup: blue ellipse
// Sound effects
// Music
// new gun asset
var GAME_W = 2048;
var GAME_H = 2732;
// State
var hero = null;
var zombies = [];
var bullets = [];
var powerups = [];
var dragNode = null;
var lastIntersecting = false;
var score = 0;
var highScore = storage.highScore || 0;
var wave = 1;
var ticksSinceStart = 0;
var zombieSpawnTick = 0;
var zombieSpawnInterval = 90; // frames
var rapidFireTicks = 0;
// --- HEALTH SYSTEM ---
var heroMaxHp = 5;
var heroHp = heroMaxHp;
// Health bar UI
var healthBarBg = new Container();
var healthBarWidth = 520;
var healthBarHeight = 38;
var healthBarBgRect = LK.getAsset('hero', {
	anchorX: 0,
	anchorY: 0,
	width: healthBarWidth,
	height: healthBarHeight,
	color: 0x333333
});
healthBarBgRect.alpha = 0.7;
healthBarBg.addChild(healthBarBgRect);
var healthBarFill = LK.getAsset('hero', {
	anchorX: 0,
	anchorY: 0,
	width: healthBarWidth,
	height: healthBarHeight,
	color: 0x3FA34D
});
healthBarFill.alpha = 0.92;
healthBarBg.addChild(healthBarFill);
healthBarBg.x = (GAME_W - healthBarWidth) / 2;
healthBarBg.y = 110;
LK.gui.top.addChild(healthBarBg);
function updateHealthBar() {
	var ratio = Math.max(0, Math.min(1, heroHp / heroMaxHp));
	healthBarFill.width = healthBarWidth * ratio;
	if (ratio > 0.6) {
		healthBarFill.tint = 0x3FA34D;
	} else if (ratio > 0.3) {
		healthBarFill.tint = 0xF7E733;
	} else {
		healthBarFill.tint = 0xD83318;
	}
}
updateHealthBar();
// Spawn hero at game start
menuActive = false;
if (hero) hero.destroy();
hero = new Hero();
hero.x = GAME_W / 2;
hero.y = GAME_H / 2;
game.addChild(hero);
// Reset state
// Move UI text declarations above their first use
var scoreTxt = new Text2('0', {
	size: 120,
	fill: "#fff"
});
scoreTxt.anchor.set(0.5, 0);
LK.gui.top.addChild(scoreTxt);
// High score text
var highScoreTxt = new Text2('Best: ' + highScore, {
	size: 60,
	fill: "#fff"
});
highScoreTxt.anchor.set(0.5, 0);
highScoreTxt.y = 120;
LK.gui.top.addChild(highScoreTxt);
// Powerup text
var powerupTxt = new Text2('', {
	size: 70,
	fill: 0x3B7DD8
});
powerupTxt.anchor.set(0.5, 0);
powerupTxt.y = 200;
LK.gui.top.addChild(powerupTxt);
heroHp = heroMaxHp;
updateHealthBar();
score = 0;
scoreTxt.setText(score);
wave = 1;
ticksSinceStart = 0;
zombieSpawnTick = 0;
zombieSpawnInterval = 90;
rapidFireTicks = 0;
for (var i = zombies.length - 1; i >= 0; i--) {
	zombies[i].destroy();
	zombies.splice(i, 1);
}
for (var i = bullets.length - 1; i >= 0; i--) {
	bullets[i].destroy();
	bullets.splice(i, 1);
}
for (var i = powerups.length - 1; i >= 0; i--) {
	powerups[i].destroy();
	powerups.splice(i, 1);
}
powerupTxt.setText('');
// --- MAIN MENU ---
var menuActive = true;
var menuOverlay = new Container();
menuOverlay.interactive = true;
menuOverlay.x = 0;
menuOverlay.y = 0;
menuOverlay.width = GAME_W;
menuOverlay.height = GAME_H;
// Dim background
var menuBg = LK.getAsset('hero', {
	anchorX: 0,
	anchorY: 0,
	width: GAME_W,
	height: GAME_H,
	color: 0x000000
});
menuBg.alpha = 0.7;
menuOverlay.addChild(menuBg);
// Title
var titleTxt = new Text2('ZOMBIE SURVIVOR', {
	size: 180,
	fill: "#fff"
});
titleTxt.anchor.set(0.5, 0.5);
titleTxt.x = GAME_W / 2;
titleTxt.y = GAME_H / 2 - 320;
menuOverlay.addChild(titleTxt);
// Instructions
var instTxt = new Text2('Drag the hero to move\nRelease to shoot\nSurvive as long as you can!', {
	size: 70,
	fill: "#fff"
});
instTxt.anchor.set(0.5, 0.5);
instTxt.x = GAME_W / 2;
instTxt.y = GAME_H / 2 - 80;
menuOverlay.addChild(instTxt);
// Start button
var startBtnBg = LK.getAsset('hero', {
	anchorX: 0.5,
	anchorY: 0.5,
	width: 520,
	height: 160,
	color: 0x3FA34D
});
startBtnBg.x = GAME_W / 2;
startBtnBg.y = GAME_H / 2 + 220;
startBtnBg.alpha = 0.93;
menuOverlay.addChild(startBtnBg);
var startBtnTxt = new Text2('START', {
	size: 110,
	fill: "#fff"
});
startBtnTxt.anchor.set(0.5, 0.5);
startBtnTxt.x = GAME_W / 2;
startBtnTxt.y = GAME_H / 2 + 220;
menuOverlay.addChild(startBtnTxt);
// Add overlay to GUI center (so it scales)
LK.gui.center.addChild(menuOverlay);
// Start button handler
menuOverlay.down = function (x, y, obj) {
	// Convert to local coordinates
	var local = LK.gui.center.toLocal({
		x: x,
		y: y
	});
	// Check if inside start button
	var bx = startBtnBg.x - startBtnBg.width / 2;
	var by = startBtnBg.y - startBtnBg.height / 2;
	if (local.x >= bx && local.x <= bx + startBtnBg.width && local.y >= by && local.y <= by + startBtnBg.height) {
		// Hide menu
		menuActive = false;
		if (menuOverlay.parent) menuOverlay.parent.removeChild(menuOverlay);
	}
};
// Show menu again on game over
var oldShowGameOver = LK.showGameOver;
LK.showGameOver = function () {
	menuActive = true;
	if (!menuOverlay.parent) LK.gui.center.addChild(menuOverlay);
	if (typeof oldShowGameOver === "function") oldShowGameOver();
};
// Helper: spawn zombie at random edge
function spawnZombie() {
	var z = new Zombie();
	// Pick edge: 0=top,1=bottom,2=left,3=right
	var edge = Math.floor(Math.random() * 4);
	var margin = 80;
	if (edge === 0) {
		// top
		z.x = margin + Math.random() * (GAME_W - 2 * margin);
		z.y = -z.radius;
	} else if (edge === 1) {
		// bottom
		z.x = margin + Math.random() * (GAME_W - 2 * margin);
		z.y = GAME_H + z.radius;
	} else if (edge === 2) {
		// left
		z.x = -z.radius;
		z.y = margin + Math.random() * (GAME_H - 2 * margin);
	} else {
		// right
		z.x = GAME_W + z.radius;
		z.y = margin + Math.random() * (GAME_H - 2 * margin);
	}
	// Set wave and type
	if (typeof z.setWave === "function") {
		z.setWave(wave);
	}
	z.target = hero;
	zombies.push(z);
	game.addChild(z);
}
// Helper: spawn powerup
function spawnPowerup() {
	var p = new Powerup();
	p.x = 200 + Math.random() * (GAME_W - 400);
	p.y = 300 + Math.random() * (GAME_H - 600);
	powerups.push(p);
	game.addChild(p);
}
// Helper: shoot bullet towards (tx,ty)
function shootBullet(tx, ty) {
	if (LK.ticks - hero.lastShotTick < (rapidFireTicks > 0 ? 6 : hero.shootCooldown)) return;
	var b = new Bullet();
	b.x = hero.x;
	b.y = hero.y;
	var dx = tx - hero.x;
	var dy = ty - hero.y;
	var dist = Math.sqrt(dx * dx + dy * dy);
	var speed = 38;
	b.vx = speed * dx / dist;
	b.vy = speed * dy / dist;
	bullets.push(b);
	game.addChild(b);
	hero.lastShotTick = LK.ticks;
	LK.getSound('shoot').play();
}
// Helper: distance between two objects
function dist2(a, b) {
	var dx = a.x - b.x;
	var dy = a.y - b.y;
	return Math.sqrt(dx * dx + dy * dy);
}
// Dragging
function handleMove(x, y, obj) {
	if (dragNode) {
		// Clamp hero inside game area
		var r = hero.radius;
		dragNode.x = Math.max(r, Math.min(GAME_W - r, x));
		dragNode.y = Math.max(r, Math.min(GAME_H - r, y));
	}
}
game.move = handleMove;
game.down = function (x, y, obj) {
	if (menuActive) return;
	// Only drag if touch is on hero
	if (dist2({
		x: x,
		y: y
	}, hero) <= hero.radius * 1.2) {
		dragNode = hero;
	}
};
game.up = function (x, y, obj) {
	if (menuActive) return;
	dragNode = null;
	// Shoot bullet towards release point if not dragging
	if (dist2({
		x: x,
		y: y
	}, hero) > hero.radius * 1.2) {
		shootBullet(x, y);
	}
};
// Main update loop
game.update = function () {
	if (menuActive) return;
	// No menuActive check; game always runs
	ticksSinceStart++;
	// Increase wave every 900 ticks (~15s)
	if (ticksSinceStart % 900 === 0) {
		wave++;
		if (zombieSpawnInterval > 30) zombieSpawnInterval -= 8;
	}
	// Spawn zombies
	if (LK.ticks - zombieSpawnTick > zombieSpawnInterval) {
		// More zombies per spawn as wave increases
		var zombiesToSpawn = 1 + Math.floor(wave / 4);
		for (var n = 0; n < zombiesToSpawn; n++) {
			spawnZombie();
		}
		zombieSpawnTick = LK.ticks;
	}
	// Maybe spawn powerup
	if (powerups.length === 0 && Math.random() < 0.002) {
		spawnPowerup();
	}
	// Update hero (nothing for now)
	hero.update();
	// Update zombies
	for (var i = zombies.length - 1; i >= 0; i--) {
		var z = zombies[i];
		z.update();
		// Check collision with hero
		if (dist2(z, hero) < z.radius + hero.radius - 10) {
			LK.effects.flashScreen(0xff0000, 400);
			heroHp--;
			updateHealthBar();
			if (heroHp <= 0) {
				if (score > highScore) {
					storage.highScore = score;
				}
				LK.showGameOver();
				return;
			}
			// Remove zombie on hit to prevent instant double hit
			z.destroy();
			zombies.splice(i, 1);
			continue;
		}
	}
	// Update bullets
	for (var i = bullets.length - 1; i >= 0; i--) {
		var b = bullets[i];
		b.update();
		// Remove if out of bounds or expired
		if (b.x < -100 || b.x > GAME_W + 100 || b.y < -100 || b.y > GAME_H + 100 || b.lifetime <= 0) {
			b.destroy();
			bullets.splice(i, 1);
			continue;
		}
		// Check collision with zombies
		for (var j = zombies.length - 1; j >= 0; j--) {
			var z = zombies[j];
			if (dist2(b, z) < b.radius + z.radius - 10) {
				// Damage zombie
				if (typeof z.hp === "number") {
					z.hp--;
					LK.effects.flashObject(z, 0xffffff, 120);
					if (z.hp <= 0) {
						LK.getSound('zombie_die').play();
						score++;
						scoreTxt.setText(score);
						if (score > highScore) {
							highScore = score;
							highScoreTxt.setText('Best: ' + highScore);
							storage.highScore = highScore;
						}
						z.destroy();
						zombies.splice(j, 1);
					}
				} else {
					// fallback: destroy if no hp
					LK.getSound('zombie_die').play();
					score++;
					scoreTxt.setText(score);
					if (score > highScore) {
						highScore = score;
						highScoreTxt.setText('Best: ' + highScore);
						storage.highScore = highScore;
					}
					z.destroy();
					zombies.splice(j, 1);
				}
				b.destroy();
				bullets.splice(i, 1);
				break;
			}
		}
	}
	// Update powerups
	for (var i = powerups.length - 1; i >= 0; i--) {
		var p = powerups[i];
		// Check collision with hero
		if (dist2(p, hero) < p.radius + hero.radius - 10) {
			LK.getSound('powerup').play();
			rapidFireTicks = 360; // 6 seconds
			powerupTxt.setText('Rapid Fire!');
			LK.effects.flashObject(hero, 0x3b7dd8, 400);
			p.destroy();
			powerups.splice(i, 1);
		}
	}
	// Powerup timer
	if (rapidFireTicks > 0) {
		rapidFireTicks--;
		if (rapidFireTicks === 0) {
			powerupTxt.setText('');
		}
	}
	// Update powerup text alpha for effect
	if (rapidFireTicks > 0) {
		powerupTxt.alpha = 0.7 + 0.3 * Math.sin(LK.ticks / 6);
	} else {
		powerupTxt.alpha = 1;
	}
};
// Start music
LK.playMusic('bgmusic', {
	fade: {
		start: 0,
		end: 0.7,
		duration: 1200
	}
});

===================================================================
--- original.js
+++ change.js
@@ -338,9 +338,89 @@
 	powerups[i].destroy();
 	powerups.splice(i, 1);
 }
 powerupTxt.setText('');
-// Show menu at start
+// --- MAIN MENU ---
+var menuActive = true;
+var menuOverlay = new Container();
+menuOverlay.interactive = true;
+menuOverlay.x = 0;
+menuOverlay.y = 0;
+menuOverlay.width = GAME_W;
+menuOverlay.height = GAME_H;
+// Dim background
+var menuBg = LK.getAsset('hero', {
+	anchorX: 0,
+	anchorY: 0,
+	width: GAME_W,
+	height: GAME_H,
+	color: 0x000000
+});
+menuBg.alpha = 0.7;
+menuOverlay.addChild(menuBg);
+// Title
+var titleTxt = new Text2('ZOMBIE SURVIVOR', {
+	size: 180,
+	fill: "#fff"
+});
+titleTxt.anchor.set(0.5, 0.5);
+titleTxt.x = GAME_W / 2;
+titleTxt.y = GAME_H / 2 - 320;
+menuOverlay.addChild(titleTxt);
+// Instructions
+var instTxt = new Text2('Drag the hero to move\nRelease to shoot\nSurvive as long as you can!', {
+	size: 70,
+	fill: "#fff"
+});
+instTxt.anchor.set(0.5, 0.5);
+instTxt.x = GAME_W / 2;
+instTxt.y = GAME_H / 2 - 80;
+menuOverlay.addChild(instTxt);
+// Start button
+var startBtnBg = LK.getAsset('hero', {
+	anchorX: 0.5,
+	anchorY: 0.5,
+	width: 520,
+	height: 160,
+	color: 0x3FA34D
+});
+startBtnBg.x = GAME_W / 2;
+startBtnBg.y = GAME_H / 2 + 220;
+startBtnBg.alpha = 0.93;
+menuOverlay.addChild(startBtnBg);
+var startBtnTxt = new Text2('START', {
+	size: 110,
+	fill: "#fff"
+});
+startBtnTxt.anchor.set(0.5, 0.5);
+startBtnTxt.x = GAME_W / 2;
+startBtnTxt.y = GAME_H / 2 + 220;
+menuOverlay.addChild(startBtnTxt);
+// Add overlay to GUI center (so it scales)
+LK.gui.center.addChild(menuOverlay);
+// Start button handler
+menuOverlay.down = function (x, y, obj) {
+	// Convert to local coordinates
+	var local = LK.gui.center.toLocal({
+		x: x,
+		y: y
+	});
+	// Check if inside start button
+	var bx = startBtnBg.x - startBtnBg.width / 2;
+	var by = startBtnBg.y - startBtnBg.height / 2;
+	if (local.x >= bx && local.x <= bx + startBtnBg.width && local.y >= by && local.y <= by + startBtnBg.height) {
+		// Hide menu
+		menuActive = false;
+		if (menuOverlay.parent) menuOverlay.parent.removeChild(menuOverlay);
+	}
+};
+// Show menu again on game over
+var oldShowGameOver = LK.showGameOver;
+LK.showGameOver = function () {
+	menuActive = true;
+	if (!menuOverlay.parent) LK.gui.center.addChild(menuOverlay);
+	if (typeof oldShowGameOver === "function") oldShowGameOver();
+};
 // Helper: spawn zombie at random edge
 function spawnZombie() {
 	var z = new Zombie();
 	// Pick edge: 0=top,1=bottom,2=left,3=right
@@ -412,8 +492,9 @@
 	}
 }
 game.move = handleMove;
 game.down = function (x, y, obj) {
+	if (menuActive) return;
 	// Only drag if touch is on hero
 	if (dist2({
 		x: x,
 		y: y
@@ -421,8 +502,9 @@
 		dragNode = hero;
 	}
 };
 game.up = function (x, y, obj) {
+	if (menuActive) return;
 	dragNode = null;
 	// Shoot bullet towards release point if not dragging
 	if (dist2({
 		x: x,
@@ -432,8 +514,9 @@
 	}
 };
 // Main update loop
 game.update = function () {
+	if (menuActive) return;
 	// No menuActive check; game always runs
 	ticksSinceStart++;
 	// Increase wave every 900 ticks (~15s)
 	if (ticksSinceStart % 900 === 0) {