/**** 
* Classes
****/
// Define the Player class
var Player = Container.expand(function () {
	var self = Container.call(this);
	var playerGraphics = self.createAsset('player', 'Player character', 0.5, 1);
	self.speed = 5;
	self.jumpPower = -22;
	self.gravity = 0.5;
	self.velocityY = 0;
	self.isJumping = false;
	self.isFlipping = false;
	self.flipRotation = 0;
	self.moveRight = function () {
		self.x += self.speed;
	};
	self.jump = function () {
		if (!self.isJumping) {
			self.isJumping = true;
			self.velocityY = self.jumpPower;
		}
	};
	self.update = function () {
		self.y += self.velocityY;
		self.velocityY += self.gravity;
		if (self.isFlipping) {
			playerGraphics.rotation += self.flipRotation;
		}
		// Check for ground collision
		if (self.y > game.height - playerGraphics.height) {
			self.y = game.height - playerGraphics.height;
			self.isJumping = false;
			self.isFlipping = false;
			playerGraphics.rotation = 0;
		}
	};
	self.flip = function () {
		if (!self.isFlipping && self.isJumping) {
			self.isFlipping = true;
			self.flipRotation = Math.PI / 16; // 22.5 degrees per frame
		}
	};
});
// Define the Obstacle class
var Obstacle = Container.expand(function () {
	var self = Container.call(this);
	var obstacleGraphics = self.createAsset('obstacle', 'Obstacle', 0.5, 1);
	self.speed = -5;
	self.move = function () {
		self.x += self.speed;
	};
	self.update = function () {
		self.move();
	};
});

/**** 
* Initialize Game
****/
var game = new LK.Game({
	backgroundColor: 0x000000 // Init game with black background
});

/**** 
* Game Code
****/
// Initialize important asset arrays
var obstacles = [];
var player = game.addChild(new Player());
// Set the player's starting position
player.x = 2048 / 4;
player.y = game.height - player.height;
// Game tick event
LK.on('tick', function () {
	// Update player
	player.update();
	// Update obstacles
	for (var i = obstacles.length - 1; i >= 0; i--) {
		obstacles[i].update();
		// Check for collision with player
		if (player.intersects(obstacles[i])) {
			// End game if collision occurs
			LK.showGameOver();
		}
		// Remove off-screen obstacles
		if (obstacles[i].x + obstacles[i].width < 0) {
			obstacles[i].destroy();
			obstacles.splice(i, 1);
		}
	}
	// Spawn obstacles
	if (LK.ticks % 120 === 0) {
		// Every 2 seconds
		var obstacle = new Obstacle();
		obstacle.x = game.width;
		obstacle.y = game.height - obstacle.height;
		obstacles.push(obstacle);
		game.addChild(obstacle);
	}
});
// Touch event listeners
game.on('down', function (obj) {
	var touchPos = obj.event.getLocalPosition(game);
	if (touchPos.x > game.width / 2) {
		player.moveRight();
	} else {
		player.jump();
	}
});
game.on('up', function (obj) {
	player.flip();
});

===================================================================
--- original.js
+++ change.js
@@ -5,9 +5,9 @@
 var Player = Container.expand(function () {
 	var self = Container.call(this);
 	var playerGraphics = self.createAsset('player', 'Player character', 0.5, 1);
 	self.speed = 5;
-	self.jumpPower = -18;
+	self.jumpPower = -22;
 	self.gravity = 0.5;
 	self.velocityY = 0;
 	self.isJumping = false;
 	self.isFlipping = false;