Adding labels and buttons

Next, in the init function, add the following code:

        _gameScene = gameScene
        
        myLabel = SKLabelNode(fontNamed:"Chalkduster")
        myLabel.text = "Score: 0";
        myLabel.fontColor = UIColor.whiteColor()
        myLabel.fontSize = 65;
        myLabel.setScale(1.0)
        myLabel.position = CGPointMake(size.width * 0.5, size.height * 0.9)
        self.addChild(myLabel)

  gameOverLabel = SKLabelNode(fontNamed:"Chalkduster")
        gameOverLabel.text = "GAMEOVER";
        gameOverLabel.fontSize = 100;
        gameOverLabel.setScale(1.0)
        gameOverLabel.position = CGPointMake(size.width * 0.5, size.height * 0.5)
        gameOverLabel.fontColor = UIColor.whiteColor()
        self.addChild(gameOverLabel)
        gameOverLabel.hidden = true

        
        playBtn = SKSpriteNode(imageNamed: "playBtn")
        playBtn.position = CGPoint(x: size.width * 0.15, y: size.height * 0.2)
 ...