John, you gotta break his carapace first!, use an air finisher a few times until the robot's like...naked, it's when you can see its skinny arms & legs lol.
then run behind it and hit "a" and do the balancing thing and move your analog stick downwards for the finishing move. otherwise you can just target its diff body parts with your guns until he collapses! XD

This post has been edited by Radagust: Sep 2 2008, 01:53 AM