===================================================================
--- original.js
+++ change.js
@@ -1,6 +1,323 @@
-/****
+/**** 
+* Plugins
+****/ 
+var tween = LK.import("@upit/tween.v1");
+
+/**** 
+* Classes
+****/ 
+// Enemy Shell Class
+var EnemyShell = Container.expand(function () {
+	var self = Container.call(this);
+	var shell = self.attachAsset('enemyShell', {
+		anchorX: 0.5,
+		anchorY: 0.5
+	});
+	self.width = shell.width;
+	self.height = shell.height;
+	self.vx = 0;
+	self.vy = 16;
+	self.update = function () {
+		self.x += self.vx;
+		self.y += self.vy;
+	};
+	return self;
+});
+// Enemy Tank Class
+var EnemyTank = Container.expand(function () {
+	var self = Container.call(this);
+	var tank = self.attachAsset('enemyTank', {
+		anchorX: 0.5,
+		anchorY: 0.5
+	});
+	self.width = tank.width;
+	self.height = tank.height;
+	// Movement
+	self.speed = 6 + Math.random() * 2 + Math.floor(LK.getScore() / 10); // Escalate with score
+	// Firing
+	self.fireInterval = 60 + Math.floor(Math.random() * 60); // 1-2s
+	self.fireCounter = 0;
+	self.update = function () {
+		self.y += self.speed;
+		self.fireCounter++;
+		if (self.fireCounter >= self.fireInterval) {
+			self.fireCounter = 0;
+			self.fire();
+		}
+	};
+	self.fire = function () {
+		var shell = new EnemyShell();
+		shell.x = self.x;
+		shell.y = self.y + self.height / 2 + shell.height / 2;
+		// Aim at player
+		var dx = player.x - shell.x;
+		var dy = player.y - shell.y;
+		var mag = Math.sqrt(dx * dx + dy * dy);
+		shell.vx = dx / mag * (14 + Math.floor(LK.getScore() / 10));
+		shell.vy = dy / mag * (14 + Math.floor(LK.getScore() / 10));
+		enemyShells.push(shell);
+		game.addChild(shell);
+		LK.getSound('enemyFire').play();
+	};
+	return self;
+});
+// Explosion effect (for destroyed tanks)
+var Explosion = Container.expand(function () {
+	var self = Container.call(this);
+	var exp = self.attachAsset('explosion', {
+		anchorX: 0.5,
+		anchorY: 0.5
+	});
+	exp.alpha = 0.7;
+	// Animate fade out and destroy
+	tween(exp, {
+		alpha: 0
+	}, {
+		duration: 350,
+		easing: tween.linear,
+		onFinish: function onFinish() {
+			self.destroy();
+		}
+	});
+	return self;
+});
+// Player Shell Class
+var PlayerShell = Container.expand(function () {
+	var self = Container.call(this);
+	var shell = self.attachAsset('playerShell', {
+		anchorX: 0.5,
+		anchorY: 0.5
+	});
+	self.width = shell.width;
+	self.height = shell.height;
+	self.speed = -32; // Upwards
+	self.update = function () {
+		self.y += self.speed;
+	};
+	return self;
+});
+// Player Tank Class
+var PlayerTank = Container.expand(function () {
+	var self = Container.call(this);
+	var tank = self.attachAsset('playerTank', {
+		anchorX: 0.5,
+		anchorY: 0.5
+	});
+	self.width = tank.width;
+	self.height = tank.height;
+	// Fire cooldown
+	self.canFire = true;
+	self.fireCooldown = 18; // frames (0.3s)
+	self.cooldownCounter = 0;
+	self.update = function () {
+		if (!self.canFire) {
+			self.cooldownCounter++;
+			if (self.cooldownCounter >= self.fireCooldown) {
+				self.canFire = true;
+				self.cooldownCounter = 0;
+			}
+		}
+	};
+	// Fire a shell
+	self.fire = function () {
+		if (self.canFire) {
+			var shell = new PlayerShell();
+			shell.x = self.x;
+			shell.y = self.y - self.height / 2 - shell.height / 2;
+			playerShells.push(shell);
+			game.addChild(shell);
+			LK.getSound('fire').play();
+			self.canFire = false;
+		}
+	};
+	return self;
+});
+
+/**** 
 * Initialize Game
-****/
+****/ 
 var game = new LK.Game({
-	backgroundColor: 0x000000
-});
\ No newline at end of file
+	backgroundColor: 0x22272b
+});
+
+/**** 
+* Game Code
+****/ 
+// Sound effects
+// Explosion: white ellipse (for flash effect)
+// Enemy shell: orange ellipse
+// Enemy tank: red box
+// Player shell: yellow ellipse
+// Player tank: green box
+// Game area
+var GAME_W = 2048;
+var GAME_H = 2732;
+// Player
+var player = new PlayerTank();
+player.x = GAME_W / 2;
+player.y = GAME_H - 350;
+game.addChild(player);
+// Arrays for game objects
+var playerShells = [];
+var enemyTanks = [];
+var enemyShells = [];
+// Score display
+var scoreTxt = new Text2('0', {
+	size: 120,
+	fill: "#fff"
+});
+scoreTxt.anchor.set(0.5, 0);
+LK.gui.top.addChild(scoreTxt);
+// Dragging
+var dragNode = null;
+// Spawn enemy timer
+var enemySpawnInterval = 90; // frames (1.5s)
+var enemySpawnCounter = 0;
+// Difficulty escalation
+function getEnemySpawnInterval() {
+	var s = LK.getScore();
+	if (s < 10) return 90;
+	if (s < 25) return 70;
+	if (s < 50) return 55;
+	return 40;
+}
+// Move handler (drag player tank)
+function handleMove(x, y, obj) {
+	if (dragNode) {
+		// Clamp to game area, avoid top 100px (menu)
+		var minX = dragNode.width / 2;
+		var maxX = GAME_W - dragNode.width / 2;
+		var minY = 100 + dragNode.height / 2;
+		var maxY = GAME_H - dragNode.height / 2;
+		dragNode.x = Math.max(minX, Math.min(maxX, x));
+		dragNode.y = Math.max(minY, Math.min(maxY, y));
+	}
+}
+game.move = handleMove;
+game.down = function (x, y, obj) {
+	// Only drag if touch is on player tank
+	var local = player.toLocal(game.toGlobal({
+		x: x,
+		y: y
+	}));
+	if (local.x > -player.width / 2 && local.x < player.width / 2 && local.y > -player.height / 2 && local.y < player.height / 2) {
+		dragNode = player;
+	}
+};
+game.up = function (x, y, obj) {
+	dragNode = null;
+};
+// Tap to fire (anywhere)
+game.tap = function (x, y, obj) {
+	player.fire();
+};
+// For compatibility, also fire on down if not dragging
+game.down = function (x, y, obj) {
+	var local = player.toLocal(game.toGlobal({
+		x: x,
+		y: y
+	}));
+	if (local.x > -player.width / 2 && local.x < player.width / 2 && local.y > -player.height / 2 && local.y < player.height / 2) {
+		dragNode = player;
+	} else {
+		player.fire();
+	}
+};
+// Main update loop
+game.update = function () {
+	// Update player
+	player.update();
+	// Update player shells
+	for (var i = playerShells.length - 1; i >= 0; i--) {
+		var shell = playerShells[i];
+		shell.update();
+		// Remove if off screen
+		if (shell.y < -shell.height / 2) {
+			shell.destroy();
+			playerShells.splice(i, 1);
+			continue;
+		}
+		// Check collision with enemy tanks
+		for (var j = enemyTanks.length - 1; j >= 0; j--) {
+			var enemy = enemyTanks[j];
+			if (shell.intersects(enemy)) {
+				// Explosion
+				var exp = new Explosion();
+				exp.x = enemy.x;
+				exp.y = enemy.y;
+				game.addChild(exp);
+				LK.getSound('explode').play();
+				// Remove both
+				shell.destroy();
+				playerShells.splice(i, 1);
+				enemy.destroy();
+				enemyTanks.splice(j, 1);
+				// Score
+				LK.setScore(LK.getScore() + 1);
+				scoreTxt.setText(LK.getScore());
+				break;
+			}
+		}
+	}
+	// Update enemy tanks
+	for (var i = enemyTanks.length - 1; i >= 0; i--) {
+		var enemy = enemyTanks[i];
+		enemy.update();
+		// Remove if off screen
+		if (enemy.y > GAME_H + enemy.height / 2) {
+			enemy.destroy();
+			enemyTanks.splice(i, 1);
+			continue;
+		}
+		// Check collision with player
+		if (enemy.intersects(player)) {
+			// Explosion
+			var exp = new Explosion();
+			exp.x = player.x;
+			exp.y = player.y;
+			game.addChild(exp);
+			LK.getSound('explode').play();
+			LK.effects.flashScreen(0xff0000, 800);
+			LK.showGameOver();
+			return;
+		}
+	}
+	// Update enemy shells
+	for (var i = enemyShells.length - 1; i >= 0; i--) {
+		var shell = enemyShells[i];
+		shell.update();
+		// Remove if off screen
+		if (shell.y > GAME_H + shell.height / 2 || shell.x < -shell.width / 2 || shell.x > GAME_W + shell.width / 2) {
+			shell.destroy();
+			enemyShells.splice(i, 1);
+			continue;
+		}
+		// Check collision with player
+		if (shell.intersects(player)) {
+			// Explosion
+			var exp = new Explosion();
+			exp.x = player.x;
+			exp.y = player.y;
+			game.addChild(exp);
+			LK.getSound('explode').play();
+			LK.effects.flashScreen(0xff0000, 800);
+			LK.showGameOver();
+			return;
+		}
+	}
+	// Spawn enemies
+	enemySpawnCounter++;
+	if (enemySpawnCounter >= getEnemySpawnInterval()) {
+		enemySpawnCounter = 0;
+		var enemy = new EnemyTank();
+		// Random x, avoid edges
+		var margin = 200;
+		enemy.x = margin + Math.random() * (GAME_W - 2 * margin);
+		enemy.y = -enemy.height / 2;
+		enemyTanks.push(enemy);
+		game.addChild(enemy);
+	}
+};
+// Set initial score
+LK.setScore(0);
+scoreTxt.setText('0');
\ No newline at end of file