public void KillEnemy(enemy en)
 {
     if (en == enemies_alive.Find(x => x.gameObject.GetInstanceID().Equals(en.gameObject.GetInstanceID()))) //test this one! ... Seems to be working - Jared
     {
         enemies_alive.Remove(en);                                                                          //remove from list!
         en.Kill();                                                                                         //for cleanup and/or custom features for this enemy type!
     }
 }