private void OnTriggerEnter(Collider other)
        {
            switch (other.gameObject.tag)
            {
            case Tags.POWERUP:
                Powerup powerup = other.GetComponent <Powerup>();

                switch (powerup.GetPowerupType())
                {
                case PowerupType.BonusPoints:
                    PlayerScore.instance.AddBonusPoints(500);
                    AudioManager.instance.Play(SoundNames.BONUS_POINTS);
                    PlayerHud.instance.ShowNotification(powerup.GetColour(), "+500!");
                    break;

                case PowerupType.DoublePoints:
                    PlayerScore.instance.DoublePoints();
                    AudioManager.instance.Play(SoundNames.DOUBLE_POINTS);
                    PlayerHud.instance.ShowNotification(powerup.GetColour(), "x2!");
                    break;

                case PowerupType.Invincibility:
                    if (godModeRoutine != null)
                    {
                        StopCoroutine(godModeRoutine);
                    }
                    godModeRoutine = StartCoroutine(ActivateGodMode(5f));
                    AudioManager.instance.Play(SoundNames.INVINCIBILITY_POINTS);
                    PlayerHud.instance.ShowNotification(powerup.GetColour(), "Invincible!");
                    break;

                default:
                    Debug.Log("Warning! Unrecognised Powerup type: " + powerup.GetPowerupType());
                    break;
                }

                powerup.Relocate();
                break;

            default:
                // Nothing to do!
                break;
            }
        }