===================================================================
--- original.js
+++ change.js
@@ -1,6 +1,263 @@
-/****
+/**** 
+* Plugins
+****/ 
+var tween = LK.import("@upit/tween.v1");
+
+/**** 
+* Classes
+****/ 
+// Bullet class
+var Bullet = Container.expand(function () {
+	var self = Container.call(this);
+	var bulletGfx = self.attachAsset('bullet', {
+		anchorX: 0.5,
+		anchorY: 0.5
+	});
+	self.radius = bulletGfx.width / 2;
+	self.speed = 32; // Fast bullet
+	self.vx = 0;
+	self.vy = 0;
+	// Set direction
+	self.setDirection = function (dx, dy) {
+		var len = Math.sqrt(dx * dx + dy * dy);
+		if (len > 0) {
+			self.vx = dx / len * self.speed;
+			self.vy = dy / len * self.speed;
+		}
+	};
+	self.update = function () {
+		self.x += self.vx;
+		self.y += self.vy;
+	};
+	return self;
+});
+// Hero class
+var Hero = Container.expand(function () {
+	var self = Container.call(this);
+	var heroGfx = self.attachAsset('hero', {
+		anchorX: 0.5,
+		anchorY: 0.5
+	});
+	// For future upgrades: health, weapon, etc.
+	self.radius = heroGfx.width / 2;
+	return self;
+});
+// Zombie class
+var Zombie = Container.expand(function () {
+	var self = Container.call(this);
+	var zombieGfx = self.attachAsset('zombie', {
+		anchorX: 0.5,
+		anchorY: 0.5
+	});
+	self.radius = zombieGfx.width / 2;
+	// Speed will be set on spawn
+	self.speed = 2 + Math.random() * 1.5; // Slight randomization
+	// Direction vector
+	self.vx = 0;
+	self.vy = 0;
+	// Set direction towards hero
+	self.setDirection = function (targetX, targetY) {
+		var dx = targetX - self.x;
+		var dy = targetY - self.y;
+		var len = Math.sqrt(dx * dx + dy * dy);
+		if (len > 0) {
+			self.vx = dx / len * self.speed;
+			self.vy = dy / len * self.speed;
+		}
+	};
+	// Move towards direction
+	self.update = function () {
+		self.x += self.vx;
+		self.y += self.vy;
+	};
+	return self;
+});
+
+/**** 
 * Initialize Game
-****/
+****/ 
 var game = new LK.Game({
-	backgroundColor: 0x000000
-});
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+	backgroundColor: 0x181818
+});
+
+/**** 
+* Game Code
+****/ 
+// Sound for shooting
+// Bullet asset: yellow box
+// Zombie asset: green ellipse
+// Hero asset: red box
+// Game area
+var GAME_W = 2048;
+var GAME_H = 2732;
+// Hero setup
+var hero = new Hero();
+hero.x = GAME_W / 2;
+hero.y = GAME_H / 2;
+game.addChild(hero);
+// Bullets and zombies arrays
+var bullets = [];
+var zombies = [];
+// Score
+var score = 0;
+var scoreTxt = new Text2('0', {
+	size: 120,
+	fill: "#fff"
+});
+scoreTxt.anchor.set(0.5, 0);
+LK.gui.top.addChild(scoreTxt);
+// Dragging
+var dragNode = null;
+// Touch/move controls
+function handleMove(x, y, obj) {
+	// Drag hero
+	if (dragNode === hero) {
+		// Clamp hero inside game area, avoid top left 100x100
+		var minX = hero.radius + 100;
+		var maxX = GAME_W - hero.radius;
+		var minY = hero.radius;
+		var maxY = GAME_H - hero.radius;
+		hero.x = Math.max(minX, Math.min(maxX, x));
+		hero.y = Math.max(minY, Math.min(maxY, y));
+	}
+}
+game.move = handleMove;
+game.down = function (x, y, obj) {
+	// Only drag if touch is on hero
+	var dx = x - hero.x;
+	var dy = y - hero.y;
+	if (dx * dx + dy * dy <= hero.radius * hero.radius) {
+		dragNode = hero;
+		handleMove(x, y, obj);
+	}
+};
+game.up = function (x, y, obj) {
+	dragNode = null;
+};
+// Shooting: tap anywhere not on hero to shoot
+game.tap = function (x, y, obj) {
+	// Don't shoot if tap is on hero
+	var dx = x - hero.x;
+	var dy = y - hero.y;
+	if (dx * dx + dy * dy <= hero.radius * hero.radius) return;
+	// Create bullet
+	var bullet = new Bullet();
+	bullet.x = hero.x;
+	bullet.y = hero.y;
+	bullet.setDirection(dx, dy);
+	bullets.push(bullet);
+	game.addChild(bullet);
+	LK.getSound('shoot').play();
+};
+game.down = function (x, y, obj) {
+	// Drag or shoot
+	var dx = x - hero.x;
+	var dy = y - hero.y;
+	if (dx * dx + dy * dy <= hero.radius * hero.radius) {
+		dragNode = hero;
+		handleMove(x, y, obj);
+	} else {
+		// Shoot
+		var bullet = new Bullet();
+		bullet.x = hero.x;
+		bullet.y = hero.y;
+		bullet.setDirection(dx, dy);
+		bullets.push(bullet);
+		game.addChild(bullet);
+		LK.getSound('shoot').play();
+	}
+};
+// Zombie spawn timer
+var zombieSpawnInterval = 90; // frames
+var zombieSpawnTimer = 0;
+// Helper: spawn zombie at random edge
+function spawnZombie() {
+	var zombie = new Zombie();
+	// Random edge: 0=top,1=bottom,2=left,3=right
+	var edge = Math.floor(Math.random() * 4);
+	var margin = 80;
+	if (edge === 0) {
+		// top
+		zombie.x = margin + Math.random() * (GAME_W - 2 * margin);
+		zombie.y = -zombie.radius;
+	} else if (edge === 1) {
+		// bottom
+		zombie.x = margin + Math.random() * (GAME_W - 2 * margin);
+		zombie.y = GAME_H + zombie.radius;
+	} else if (edge === 2) {
+		// left
+		zombie.x = -zombie.radius;
+		zombie.y = margin + Math.random() * (GAME_H - 2 * margin);
+	} else {
+		// right
+		zombie.x = GAME_W + zombie.radius;
+		zombie.y = margin + Math.random() * (GAME_H - 2 * margin);
+	}
+	zombie.setDirection(hero.x, hero.y);
+	zombies.push(zombie);
+	game.addChild(zombie);
+}
+// Main update loop
+game.update = function () {
+	// Update zombies
+	for (var i = zombies.length - 1; i >= 0; i--) {
+		var z = zombies[i];
+		// Always update direction towards hero
+		z.setDirection(hero.x, hero.y);
+		z.update();
+		// Check collision with hero
+		var dx = z.x - hero.x;
+		var dy = z.y - hero.y;
+		var dist = Math.sqrt(dx * dx + dy * dy);
+		if (dist < z.radius + hero.radius - 10) {
+			// Game over
+			LK.effects.flashScreen(0xff0000, 1000);
+			LK.showGameOver();
+			return;
+		}
+	}
+	// Update bullets
+	for (var j = bullets.length - 1; j >= 0; j--) {
+		var b = bullets[j];
+		b.update();
+		// Remove if out of bounds
+		if (b.x < -b.radius || b.x > GAME_W + b.radius || b.y < -b.radius || b.y > GAME_H + b.radius) {
+			b.destroy();
+			bullets.splice(j, 1);
+			continue;
+		}
+		// Check collision with zombies
+		for (var k = zombies.length - 1; k >= 0; k--) {
+			var z2 = zombies[k];
+			var dx2 = b.x - z2.x;
+			var dy2 = b.y - z2.y;
+			var dist2 = Math.sqrt(dx2 * dx2 + dy2 * dy2);
+			if (dist2 < b.radius + z2.radius - 10) {
+				// Zombie killed
+				z2.destroy();
+				zombies.splice(k, 1);
+				b.destroy();
+				bullets.splice(j, 1);
+				// Score up
+				score += 1;
+				scoreTxt.setText(score);
+				break;
+			}
+		}
+	}
+	// Spawn zombies
+	zombieSpawnTimer++;
+	if (zombieSpawnTimer >= zombieSpawnInterval) {
+		spawnZombie();
+		zombieSpawnTimer = 0;
+		// Gradually increase spawn rate
+		if (zombieSpawnInterval > 30) zombieSpawnInterval -= 1;
+	}
+};
+// Center hero on start
+hero.x = GAME_W / 2;
+hero.y = GAME_H / 2;
+// Initial zombie spawn
+for (var i = 0; i < 3; i++) {
+	spawnZombie();
+}
\ No newline at end of file