===================================================================
--- original.js
+++ change.js
@@ -1,6 +1,382 @@
-/****
+/**** 
+* Plugins
+****/ 
+var tween = LK.import("@upit/tween.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 * 0.5;
+	self.speed = 32;
+	self.dx = 0;
+	self.dy = 0;
+	self.update = function () {
+		self.x += self.dx * self.speed;
+		self.y += self.dy * self.speed;
+	};
+	return self;
+});
+// Enemy class
+var Enemy = Container.expand(function () {
+	var self = Container.call(this);
+	var enemySprite = self.attachAsset('enemy', {
+		anchorX: 0.5,
+		anchorY: 0.5
+	});
+	self.radius = enemySprite.width * 0.5;
+	self.speed = 6 + Math.random() * 4;
+	self.hp = 2;
+	self.target = null; // set to player
+	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 += dx / dist * self.speed;
+			self.y += dy / dist * self.speed;
+		}
+	};
+	self.hit = function () {
+		self.hp--;
+		LK.getSound('enemyhit').play();
+		LK.effects.flashObject(self, 0xffffff, 120);
+		if (self.hp <= 0) {
+			self.destroyed = true;
+		}
+	};
+	return self;
+});
+// Player class
+var Player = Container.expand(function () {
+	var self = Container.call(this);
+	var playerSprite = self.attachAsset('player', {
+		anchorX: 0.5,
+		anchorY: 0.5
+	});
+	self.radius = playerSprite.width * 0.5;
+	self.speed = 18;
+	self.hp = 5;
+	self.invuln = 0; // frames of invulnerability after hit
+	// For upgrades
+	self.fireRate = 24; // frames between shots
+	self.bulletSpeed = 32;
+	self.bulletSpread = 0; // degrees
+	self.lastShot = 0;
+	self.update = function () {
+		if (self.invuln > 0) {
+			self.invuln--;
+			playerSprite.alpha = 0.5 + 0.5 * Math.sin(LK.ticks * 0.4);
+		} else {
+			playerSprite.alpha = 1;
+		}
+	};
+	// Called when player is hit
+	self.hit = function () {
+		if (self.invuln > 0) return;
+		self.hp--;
+		self.invuln = 60;
+		LK.effects.flashObject(self, 0xff0000, 400);
+		LK.getSound('playerhit').play();
+		updateHpText();
+		if (self.hp <= 0) {
+			LK.effects.flashScreen(0xff0000, 1200);
+			LK.showGameOver();
+		}
+	};
+	// Called when player picks up a powerup
+	self.applyPowerup = function (type) {
+		if (type === 'firerate') {
+			self.fireRate = Math.max(8, self.fireRate - 4);
+		} else if (type === 'spread') {
+			self.bulletSpread = Math.min(30, self.bulletSpread + 10);
+		} else if (type === 'hp') {
+			self.hp = Math.min(8, self.hp + 1);
+			updateHpText();
+		} else if (type === 'bulletspeed') {
+			self.bulletSpeed = Math.min(48, self.bulletSpeed + 4);
+		}
+	};
+	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 * 0.5;
+	self.type = 'firerate'; // default, can be changed
+	self.update = function () {};
+	return self;
+});
+
+/**** 
 * Initialize Game
-****/
+****/ 
 var game = new LK.Game({
-	backgroundColor: 0x000000
-});
\ No newline at end of file
+	backgroundColor: 0x7c3f1c
+});
+
+/**** 
+* Game Code
+****/ 
+// Music
+// Sound effects
+// Martian ground (background)
+// Powerup
+// Bullet
+// Enemy
+// Player
+// Add background
+var marsbg = LK.getAsset('marsbg', {
+	anchorX: 0,
+	anchorY: 0,
+	x: 0,
+	y: 0
+});
+game.addChild(marsbg);
+// Game variables
+var player;
+var enemies = [];
+var bullets = [];
+var powerups = [];
+var dragNode = null;
+var lastMoveX = 0,
+	lastMoveY = 0;
+var score = 0;
+var timeLeft = 20 * 60; // 20 minutes in seconds, but we use frames (20*60*60)
+var timerFrames = 20 * 60 * 60; // 20 minutes * 60 seconds * 60 frames
+var lastEnemySpawn = 0;
+var enemySpawnInterval = 90; // frames
+var lastPowerupSpawn = 0;
+var powerupInterval = 900; // every 15 seconds
+// GUI
+var scoreTxt = new Text2('Score: 0', {
+	size: 90,
+	fill: "#fff"
+});
+scoreTxt.anchor.set(0.5, 0);
+LK.gui.top.addChild(scoreTxt);
+var timerTxt = new Text2('20:00', {
+	size: 90,
+	fill: "#fff"
+});
+timerTxt.anchor.set(0.5, 0);
+LK.gui.top.addChild(timerTxt);
+var hpTxt = new Text2('HP: 5', {
+	size: 90,
+	fill: "#fff"
+});
+hpTxt.anchor.set(1, 0);
+LK.gui.topRight.addChild(hpTxt);
+function updateScoreText() {
+	scoreTxt.setText('Score: ' + score);
+}
+function updateTimerText() {
+	var seconds = Math.floor(timerFrames / 60);
+	var min = Math.floor(seconds / 60);
+	var sec = seconds % 60;
+	var t = (min < 10 ? '0' : '') + min + ':' + (sec < 10 ? '0' : '') + sec;
+	timerTxt.setText(t);
+}
+function updateHpText() {
+	if (player) hpTxt.setText('HP: ' + player.hp);
+}
+// Spawn player in center
+player = new Player();
+player.x = 2048 / 2;
+player.y = 2732 / 2;
+game.addChild(player);
+// Music
+LK.playMusic('marsmusic');
+// Move handler (drag to move player)
+function handleMove(x, y, obj) {
+	if (dragNode) {
+		// Clamp to game area
+		var px = Math.max(player.radius, Math.min(2048 - player.radius, x));
+		var py = Math.max(player.radius, Math.min(2732 - player.radius, y));
+		dragNode.x = px;
+		dragNode.y = py;
+		lastMoveX = px;
+		lastMoveY = py;
+	}
+}
+game.move = handleMove;
+game.down = function (x, y, obj) {
+	// Only start drag if touch is not in top left 100x100
+	if (x > 100 || y > 100) {
+		dragNode = player;
+		handleMove(x, y, obj);
+	}
+};
+game.up = function (x, y, obj) {
+	dragNode = null;
+};
+// Fire bullets automatically
+function fireBullets() {
+	if (LK.ticks - player.lastShot < player.fireRate) return;
+	player.lastShot = LK.ticks;
+	var spread = player.bulletSpread;
+	var angles = [0];
+	if (spread > 0) {
+		angles = [-spread, 0, spread];
+	}
+	for (var i = 0; i < angles.length; i++) {
+		var angle = angles[i] * Math.PI / 180;
+		var b = new Bullet();
+		b.x = player.x;
+		b.y = player.y;
+		b.speed = player.bulletSpeed;
+		b.dx = Math.sin(angle);
+		b.dy = -Math.cos(angle);
+		bullets.push(b);
+		game.addChild(b);
+	}
+	LK.getSound('shoot').play();
+}
+// Spawn enemies at random edge
+function spawnEnemy() {
+	var e = new Enemy();
+	// Pick random edge
+	var edge = Math.floor(Math.random() * 4);
+	var ex, ey;
+	if (edge === 0) {
+		// top
+		ex = Math.random() * 2048;
+		ey = -e.radius - 10;
+	} else if (edge === 1) {
+		// right
+		ex = 2048 + e.radius + 10;
+		ey = Math.random() * 2732;
+	} else if (edge === 2) {
+		// bottom
+		ex = Math.random() * 2048;
+		ey = 2732 + e.radius + 10;
+	} else {
+		// left
+		ex = -e.radius - 10;
+		ey = Math.random() * 2732;
+	}
+	e.x = ex;
+	e.y = ey;
+	e.target = player;
+	enemies.push(e);
+	game.addChild(e);
+}
+// Spawn powerup at random location
+function spawnPowerup() {
+	var p = new Powerup();
+	var types = ['firerate', 'spread', 'hp', 'bulletspeed'];
+	p.type = types[Math.floor(Math.random() * types.length)];
+	p.x = 200 + Math.random() * (2048 - 400);
+	p.y = 200 + Math.random() * (2732 - 400);
+	powerups.push(p);
+	game.addChild(p);
+}
+// Main update loop
+game.update = function () {
+	// Timer
+	if (timerFrames > 0) {
+		timerFrames--;
+		updateTimerText();
+	}
+	if (timerFrames === 0) {
+		LK.effects.flashScreen(0x00ff00, 1200);
+		LK.showYouWin();
+		return;
+	}
+	// Player update
+	player.update();
+	// Fire bullets
+	fireBullets();
+	// Bullets update
+	for (var i = bullets.length - 1; i >= 0; i--) {
+		var b = bullets[i];
+		b.update();
+		// Remove if off screen
+		if (b.x < -60 || b.x > 2048 + 60 || b.y < -60 || b.y > 2732 + 60) {
+			b.destroy();
+			bullets.splice(i, 1);
+			continue;
+		}
+		// Check collision with enemies
+		for (var j = enemies.length - 1; j >= 0; j--) {
+			var e = enemies[j];
+			var dx = b.x - e.x;
+			var dy = b.y - e.y;
+			var dist = Math.sqrt(dx * dx + dy * dy);
+			if (dist < b.radius + e.radius) {
+				e.hit();
+				if (e.hp <= 0) {
+					e.destroy();
+					enemies.splice(j, 1);
+					score += 10;
+					updateScoreText();
+				}
+				b.destroy();
+				bullets.splice(i, 1);
+				break;
+			}
+		}
+	}
+	// Enemies update
+	for (var i = enemies.length - 1; i >= 0; i--) {
+		var e = enemies[i];
+		e.update();
+		// Check collision with player
+		var dx = e.x - player.x;
+		var dy = e.y - player.y;
+		var dist = Math.sqrt(dx * dx + dy * dy);
+		if (dist < e.radius + player.radius) {
+			player.hit();
+			e.destroy();
+			enemies.splice(i, 1);
+			continue;
+		}
+		// Remove if off screen (shouldn't happen, but just in case)
+		if (e.x < -200 || e.x > 2048 + 200 || e.y < -200 || e.y > 2732 + 200) {
+			e.destroy();
+			enemies.splice(i, 1);
+		}
+	}
+	// Powerups update
+	for (var i = powerups.length - 1; i >= 0; i--) {
+		var p = powerups[i];
+		// Check collision with player
+		var dx = p.x - player.x;
+		var dy = p.y - player.y;
+		var dist = Math.sqrt(dx * dx + dy * dy);
+		if (dist < p.radius + player.radius) {
+			player.applyPowerup(p.type);
+			LK.getSound('powerup').play();
+			p.destroy();
+			powerups.splice(i, 1);
+			continue;
+		}
+	}
+	// Enemy spawn logic (increase spawn rate over time)
+	if (LK.ticks - lastEnemySpawn > enemySpawnInterval) {
+		spawnEnemy();
+		lastEnemySpawn = LK.ticks;
+		// Gradually increase spawn rate
+		if (enemySpawnInterval > 30) enemySpawnInterval -= 0.02;
+	}
+	// Powerup spawn logic
+	if (LK.ticks - lastPowerupSpawn > powerupInterval) {
+		spawnPowerup();
+		lastPowerupSpawn = LK.ticks;
+	}
+};
+// Initial GUI update
+updateScoreText();
+updateTimerText();
+updateHpText();
\ No newline at end of file