var Obstacle = Container.expand(function () {
	var self = Container.call(this);
	var obstacleGraphics = self.createAsset('obstacle', 'Obstacle', .5, .5);
	obstacleGraphics.rotation = Math.PI / 4;
	self.speed = 5;
	self.move = function () {
		self.y += self.speed;
		if (self.y > 2732) {
			self.y = 0;
		}
	};
});
var Wall = Container.expand(function () {
	var self = Container.call(this);
	var wallGraphics = self.createAsset('wall', 'Wall', .5, .5);
});
var Bird = Container.expand(function () {
	var self = Container.call(this);
	var birdGraphics = self.createAsset('bird', 'Bird character', .5, .5);
	birdGraphics.scale.x = 1;
	self.xSpeed = 8.75;
	self.ySpeed = 0;
	self.gravity = 0.5;
	self.lift = -15;
	self.flap = function () {
		self.ySpeed = self.lift * 1.25;
	};
	self.update = function () {
		self.ySpeed += self.gravity;
		self.y += self.ySpeed;
		self.x += self.xSpeed;
		if (self.y <= 0 || self.y >= 2732) {
			self.speed = -self.speed;
		}
		var targetRotation = Math.atan2(self.ySpeed, self.xSpeed * self.scale.x) / 2 + Math.PI / 12;
		birdGraphics.rotation += (targetRotation - birdGraphics.rotation) / 10;
	};
	self.flip = function () {
		self.scale.x *= -1;
	};
});
var Game = Container.expand(function () {
	var self = Container.call(this);
	self.checkObstacleCollision = function (obstacles) {
		for (var i = 0; i < obstacles.length; i++) {
			obstacles[i].move();
			var dist = Math.sqrt(Math.pow(bird.x - obstacles[i].x, 2) + Math.pow(bird.y - obstacles[i].y, 2));
			if (dist < 250) {
				LK.showGameOver();
			}
		}
	};
	LK.stageContainer.setBackgroundColor(0xadd8e6);
	var bird = self.addChild(new Bird());
	var leftWall = self.addChild(new Wall());
	leftWall.x = 0;
	leftWall.y = 1366;
	var rightWall = self.addChild(new Wall());
	rightWall.x = 2048;
	rightWall.y = 1366;
	var leftObstacles = [], rightObstacles = [];
	var obstacleSpawnRandomness = 120;
	var obstacleSpawnY = -100;
	var leftObstacleSpawnTime = Math.floor(Math.random() * obstacleSpawnRandomness) + obstacleSpawnRandomness;
	var rightObstacleSpawnTime = Math.floor(Math.random() * obstacleSpawnRandomness) + obstacleSpawnRandomness;
	bird.x = 1024;
	bird.y = 1366;
	stage.on('down', function (obj) {
		bird.flap();
	});
	LK.on('tick', function () {
		bird.update();
		if (LK.ticks == leftObstacleSpawnTime) {
			var newObstacle = self.addChild(new Obstacle());
			newObstacle.x = 0;
			newObstacle.y = obstacleSpawnY;
			leftObstacles.push(newObstacle);
			leftObstacleSpawnTime += Math.floor(Math.random() * obstacleSpawnRandomness) + obstacleSpawnRandomness;
		}
		if (LK.ticks == rightObstacleSpawnTime) {
			var newObstacle = self.addChild(new Obstacle());
			newObstacle.x = 2048;
			newObstacle.y = -newObstacle.height;
			rightObstacles.push(newObstacle);
			rightObstacleSpawnTime += Math.floor(Math.random() * obstacleSpawnRandomness) + obstacleSpawnRandomness;
		}
		if (bird.intersects(leftWall) && bird.xSpeed < 0 || bird.intersects(rightWall) && bird.xSpeed > 0) {
			bird.xSpeed = -bird.xSpeed;
			bird.flip();
		}
		self.checkObstacleCollision(leftObstacles);
		self.checkObstacleCollision(rightObstacles);
		if (bird.y < 0 || bird.y > 2732) {
			LK.showGameOver();
		}
	});
});

===================================================================
--- original.js
+++ change.js
@@ -31,9 +31,9 @@
 		self.x += self.xSpeed;
 		if (self.y <= 0 || self.y >= 2732) {
 			self.speed = -self.speed;
 		}
-		var targetRotation = Math.atan2(self.ySpeed, self.xSpeed * self.scale.x) / 2 + Math.PI / 6;
+		var targetRotation = Math.atan2(self.ySpeed, self.xSpeed * self.scale.x) / 2 + Math.PI / 12;
 		birdGraphics.rotation += (targetRotation - birdGraphics.rotation) / 10;
 	};
 	self.flip = function () {
 		self.scale.x *= -1;