>>893
Unityよく分からんが多分これでいける


if (Input.GetKeyDown (KeyCode.X) )
{
GameObject clone = Instantiate (bullet2, transform.position, Quaternion.identity) as GameObject; //弾の生成
  clone.GetComponent<Rigidbody2D> ().velocity = new Vector2 (0, 15);       //弾をy軸15へ飛ばす
}
else if (Input.GetKeyDown (KeyCode.Z) )
{
GameObject clone = Instantiate (bullet, transform.position, Quaternion.identity) as GameObject; //弾の生成
  clone.GetComponent<Rigidbody2D> ().velocity = new Vector2 (0, 15);       //弾をy軸15へ飛ばす
}