===================================================================
--- original.js
+++ change.js
@@ -1,84 +1,89 @@
-/****
+/**** 
 * Classes
 ****/
 var Dot = Container.expand(function () {
-  var self = Container.call(this);
-  var dotGraphics = self.attachAsset('dot', {
-    anchorX: 0.5,
-    anchorY: 0.5
-  });
-  self.velocityY = 0;
-  self.gravity = 0.5;
-  self.bounce = -15;
-  self.update = function () {
-    self.velocityY += self.gravity;
-    self.y += self.velocityY;
-    if (self.y > 2732 - self.height / 2) {
-      self.velocityY = self.bounce;
-    }
-  };
-  self.bounceUp = function () {
-    self.velocityY = self.bounce;
-  };
+	var self = Container.call(this);
+	var dotGraphics = self.attachAsset('dot', {
+		anchorX: 0.5,
+		anchorY: 0.5
+	});
+	self.velocityY = 0;
+	self.gravity = 0.5;
+	self.bounce = -15;
+	self.update = function () {
+		self.velocityY += self.gravity;
+		self.y += self.velocityY;
+		if (self.y > 2732 - self.height / 2) {
+			self.velocityY = self.bounce;
+		}
+	};
+	self.bounceUp = function () {
+		self.velocityY = self.bounce;
+	};
 });
 var Obstacle = Container.expand(function () {
-  var self = Container.call(this);
-  var obstacleGraphics = self.attachAsset('obstacle', {
-    anchorX: 0.5,
-    anchorY: 0.5
-  });
-  self.speed = -5;
-  self.move = function () {
-    self.x += self.speed;
-    if (self.x < -self.width / 2) {
-      self.x = 2048 + self.width / 2;
-      self.y = Math.random() * (2732 - self.height) + self.height / 2;
-    }
-  };
+	var self = Container.call(this);
+	var obstacleGraphics = self.attachAsset('obstacle', {
+		anchorX: 0.5,
+		anchorY: 0.5
+	});
+	self.speed = -5;
+	self.move = function (offsetY) {
+		self.x += self.speed;
+		if (self.x < -self.width / 2) {
+			self.x = 2048 + self.width / 2;
+			self.y = Math.random() * (2732 - self.height) + self.height / 2;
+		}
+		if (offsetY) {
+			self.y += offsetY;
+		}
+	};
 });
 
-/****
+/**** 
 * Initialize Game
 ****/
 var game = new LK.Game({
-  backgroundColor: 0x000000
+	backgroundColor: 0x000000
 });
 
-/****
+/**** 
 * Game Code
 ****/
 var dot = game.addChild(new Dot());
 dot.x = 2048 / 2;
 dot.y = 2732 / 2;
 var obstacles = [];
 for (var i = 0; i < 5; i++) {
-  var obstacle = game.addChild(new Obstacle());
-  obstacle.x = 2048 / 2 + i * 450;
-  obstacle.y = Math.random() * (2732 - obstacle.height) + obstacle.height / 2;
-  obstacles.push(obstacle);
+	var obstacle = game.addChild(new Obstacle());
+	obstacle.x = 2048 / 2 + i * 450;
+	obstacle.y = Math.random() * (2732 - obstacle.height) + obstacle.height / 2;
+	obstacles.push(obstacle);
 }
 var scoreTxt = new Text2('0', {
-  size: 150,
-  fill: "#ffffff"
+	size: 150,
+	fill: "#ffffff"
 });
 scoreTxt.anchor.set(0.5, 0);
 scoreTxt.x = 2048 / 2;
 scoreTxt.y = 50;
 LK.gui.top.addChild(scoreTxt);
 game.on('down', function (obj) {
-  dot.bounceUp();
+	dot.bounceUp();
 });
 LK.on('tick', function () {
-  dot.update();
-  for (var i = 0; i < obstacles.length; i++) {
-    obstacles[i].move();
-    if (dot.intersects(obstacles[i])) {
-      LK.effects.flashScreen(0xff0000, 1000);
-      LK.showGameOver();
-    }
-  }
-  // Update score based on the dot's survival time
-  var currentScore = Math.floor(LK.ticks / 60);
-  LK.setScore(currentScore);
-  scoreTxt.setText(LK.getScore().toString());
+	var previousY = dot.y;
+	dot.update();
+	var offsetY = previousY - dot.y;
+	for (var i = 0; i < obstacles.length; i++) {
+		obstacles[i].move(offsetY > 0 ? offsetY : 0);
+		if (dot.intersects(obstacles[i])) {
+			LK.effects.flashScreen(0xff0000, 1000);
+			LK.showGameOver();
+		}
+	}
+	// Update score based on the dot's survival time
+	var currentScore = Math.floor(LK.ticks / 60);
+	LK.setScore(currentScore);
+	scoreTxt.setText(LK.getScore().toString());
 });
\ No newline at end of file