This game was pretty easy. The last two extreme challenges were a pain IMO. Takes roughly 15 hours to 100%. Just a heads up, you don't need another player for the multiplayer achievement. I got them by myself.
EDIT: Another thing that was a pain is when you do duels on the blackboard. Your opponent is random so you don't know who you're going to get.
Last edited by Skorpion x360a; 10-22-2012 at 02:42 PM.