// Start is called before the first frame update
    void Start()
    {
        button = GetComponent <Button>();
        button.onClick.AddListener(SetDifficulty);

        gameManager = GameObject.Find("GameManager").GetComponent <GameManagerCH4>();
    }
 void Start()
 {
     enemyRb     = GetComponent <Rigidbody>();
     player      = GameObject.Find("Player");
     gameManager = GameObject.Find("GameManager").GetComponent <GameManagerCH4>();
 }
 void Start()
 {
     playerRb    = GetComponent <Rigidbody>();
     focalPoint  = GameObject.Find("Focal Point");
     gameManager = GameObject.Find("GameManager").GetComponent <GameManagerCH4>();
 }