===================================================================
--- original.js
+++ change.js
@@ -1,7 +1,22 @@
 /**** 
 * Classes
 ****/
+var Stopwatch = Container.expand(function () {
+	var self = Container.call(this);
+	var time = 0;
+	var stopwatchText = new Text2('00:00', {
+		size: 100,
+		fill: "#ffffff"
+	});
+	self.addChild(stopwatchText);
+	self.update = function (delta) {
+		time += delta;
+		var minutes = Math.floor(time / 60000);
+		var seconds = Math.floor(time % 60000 / 1000);
+		stopwatchText.setText(minutes.toString().padStart(2, '0') + ':' + seconds.toString().padStart(2, '0'));
+	};
+});
 // Hero class
 var Hero = Container.expand(function () {
 	var self = Container.call(this);
 	var heroGraphics = self.attachAsset('hero', {
@@ -64,8 +79,12 @@
 
 /**** 
 * Game Code
 ****/
+// Initialize stopwatch
+var stopwatch = game.addChild(new Stopwatch());
+stopwatch.x = 2048 / 2 - stopwatch.width / 2;
+stopwatch.y = 50;
 // Define assets for the hero, enemies, and bullets
 // Initialize hero
 var hero = game.addChild(new Hero());
 hero.x = 2048 / 2;
@@ -119,8 +138,10 @@
 			enemyBullets[k].destroy();
 			enemyBullets.splice(k, 1);
 		}
 	}
+	// Update stopwatch
+	stopwatch.update(LK.delta);
 	// Hero shooting logic
 	if (LK.ticks % 60 == 0) {
 		var bullet = new HeroBullet();
 		bullet.x = hero.x;