$ basic 2D game example

/* basic 2D game example */
var game = new Phaser.Game(800, 600, Phaser.AUTO, '', { preload: preload, create: create, update: update });
function preload() {
  game.load.image('sky', 'assets/sky.png');
  game.load.image('ground', 'assets/platform.png');
  game.load.image('star', 'assets/star.png');
  game.load.spritesheet('dude', 'assets/dude.png', 32, 48);
}
var platforms;
var player;
var cursors;
var stars;
var score = 0;
var scoreText;
function create() {
  game.physics.startSystem(Phaser.Physics.ARCADE);
  game.add.sprite(0, 0, 'sky');
  platforms = game.add.group();
  platforms.enableBody = true;
  var ground = platforms.create(0, game.world.height - 64, 'ground');
  ground.scale.setTo(2, 2);
  ground.body.immovable = true;
  var ledge = platforms.create(400, 400, 'ground');
  ledge.body.immovable = true;
  ledge = platforms.create(-150, 250, 'ground');
  ledge.body.immovable = true;
  player = game.add.sprite(32, game.world.height - 150, 'dude');
  game.physics.arcade.enable(player);
  player.body.bounce.y = 0.2;
  player.body.gravity.y = 300;
  player.body.collideWorldBounds = true;
  player.animations.add('left', [0, 1, 2, 3], 10, true);
  player.animations.add('right', [5, 6, 7, 8], 10, true);
  cursors = game.input.keyboard.createCursorKeys();
  stars = game.add.group();
  stars.enableBody = true;
  for (var i = 0; i < 12; i++) {
    var star = stars.create(i * 70, 0, 'star');
    star.body.gravity.y = 6;
    star.body.bounce.y = 0.7 + Math.random() * 0.2;
  }
  scoreText = game.add.text(16, 16, 'score: 0', { fontSize: '32px', fill: '#000' });
}
function update() {
  game.physics.arcade.collide(player, platforms);
  game.physics.arcade.collide(stars, platforms);
  game.physics.arcade.overlap(player, stars, collectStar, null, this);
  player.body.velocity.x = 0;
  if (cursors.left.isDown) {
    player.body.velocity.x = -150;
    player.animations.play('left');
  } else if (cursors.right.isDown) {
    player.body.velocity.x = 150;
    player.animations.play('right');
  } else {
    player.animations.stop();
    player.frame = 4;
  }
  if (cursors.up.isDown && player.body.touching.down) {
    player.body.velocity.y = -350;
  }
}
function collectStar(player, star) {
  star.kill();
  score += 10;
  scoreText.text = 'Score: ' + score;
}