Threw this game in because the last two achievements were bugging me. I got head chomper and now I cant seem to confirm whether or not various solutions to the "Perfect Fight" achievement has been patched. Hopping between the two sites (x360a & truea) it seems the easiest method now would be to start the match with the primary profile then have a second controller join the game and stand still. Try to do as much damage to his first form as possible before you run out of lives (can't confirm if the achievement will still unlock if the secondary profile uses continues) and then the rest is all you. Im going to try the method listed in the updated achievement guide so I can confirm whether or not it still works.
Rayman Origins / Joe Danger SE
War of the Worlds
"The dumber people think you are, the more suprised they are going to be when you kill them."