void OnTriggerEnter2D(Collider2D other) { if (other.IsProjectile ()) { var projectile = other.GetComponent<Projectile> (); if (projectile.IsTargetingAlien) { Score.Instance.Sum (m_alien.gameObject); m_alien.Die (); } } else if (other.IsCannonZone ()) { Cannon.Instance.Die (); } }