Unlocking Achievements

#1Acky_316Posted 12/28/2011 6:56:01 PM
Hey guys, I just picked this game up with my fiancee to play in our downtime. I was wondering, all of the achievements are single-player only. Do I need to have 2 separate files, one for co-op and one for single player, to unlock them? Or can we go through it in co-op, then go back in Free Play and unlock them later?