var Target = Container.expand(function () {
	var self = Container.call(this);
	var targetGraphics = self.createAsset('target', 'Target Graphics', .5, .5);
	self.speed = 0.01;
	self.circleSize = 700;
	self.rotate = function (centerX, centerY) {
		var angle = Math.atan2(self.y - centerY, self.x - centerX) + self.speed;
		self.x = centerX + Math.cos(angle) * self.circleSize;
		self.y = centerY + Math.sin(angle) * self.circleSize;
	};
});
var Game = Container.expand(function () {
	var self = Container.call(this);
	var centerX = 2048 / 2;
	var centerY = 2732 / 2;
	var dot = self.addChild(new Dot());
	dot.x = centerX + dot.circleSize;
	dot.y = centerY;
	var target = self.addChild(new Target());
	target.x = centerX - target.circleSize;
	target.y = centerY;
	var scoreTxt = new Text2('0', {
		size: 150,
		fill: "#ffffff"
	});
	scoreTxt.anchor.set(.5, 0);
	LK.gui.topCenter.addChild(scoreTxt);
	var score = 0;
	var isGameOver = false;
	dot.on('down', function (obj) {
		if (Math.abs(dot.x - centerX) < 50) {
			score++;
			scoreTxt.setText(score);
		} else {
			isGameOver = true;
		}
	});
	LK.on('tick', function () {
		if (isGameOver) {
			LK.effects.flashScreen(0xff0000, 1000);
			LK.showGameOver();
		} else {
			dot.rotate(centerX, centerY);
		}
	});
});

===================================================================
--- original.js
+++ change.js
@@ -1,7 +1,7 @@
-var Dot = Container.expand(function () {
+var Target = Container.expand(function () {
 	var self = Container.call(this);
-	var dotGraphics = self.createAsset('dot', 'Dot Graphics', .5, .5);
+	var targetGraphics = self.createAsset('target', 'Target Graphics', .5, .5);
 	self.speed = 0.01;
 	self.circleSize = 700;
 	self.rotate = function (centerX, centerY) {
 		var angle = Math.atan2(self.y - centerY, self.x - centerX) + self.speed;
@@ -15,8 +15,11 @@
 	var centerY = 2732 / 2;
 	var dot = self.addChild(new Dot());
 	dot.x = centerX + dot.circleSize;
 	dot.y = centerY;
+	var target = self.addChild(new Target());
+	target.x = centerX - target.circleSize;
+	target.y = centerY;
 	var scoreTxt = new Text2('0', {
 		size: 150,
 		fill: "#ffffff"
 	});