private void OnCollisionEnter(Collision collision)
 {
     if (collision.collider.tag == "Bullet")
     {
         scoreSound.Play();
         isAlive = false;
         animator.SetBool("isAlive", isAlive);
         player.AddScore(1);
         player.AddAmmo(1);
     }
     else
     {
         isAlive = true;
     }
 }