title: Unity transform.LookAt in only one axis
body: <p>I've been working on a game and it's going really nice. Got some help from here and I need it again. So I'm making a 2D top-down shooter and I need my enemy to look at the player, and obviously the enemy will rotate in all axis and thus being invincible or will look really weird. So, how do I make it rotate only in the Z axis ? Also if you are going to provide and answer I need it done in UnityScript.</p>
  
  <p><a href="https://i.stack.imgur.com/FbOJC.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/FbOJC.png" alt="enter image description here"></a></p>