slow down effect

slowdown.cs

    IEnumerator SpawnPowerupRoutine()
    {
        //every 3 - 7 seconds, spawn in a powerup
        while (_stopSpawning == false)
        {
            float _randomSpawnPosition = Random.Range(-9.0f, 9.0f);
            Vector3 spawn = new Vector3(_randomSpawnPosition, 7, 0);
            
            _randomPowerup = Random.Range(0, 7);
            if (_bigLaserCount == 5)
            {
                Instantiate(_powerups[6], spawn, Quaternion.identity);
                _bigLaserCount = 0;

            }
            else
            {
                _randomPowerup = Random.Range(0, 6);
                Instantiate(_powerups[_randomPowerup], spawn, Quaternion.identity);
                _bigLaserCount++;
            }


            yield return new WaitForSeconds(Random.Range(3, 8));
        }
    }