Marvel Ultimate Alliance 2

The first achievement in this set is required to be done in co-op, but you'll probably want to do all these in co-op to get the Gold medals easier, though you do not have to. Once you have all 12 Simulator Discs from the campaign, give these a go. The locations of the discs can be found in the collectibles guide. For all of the mission requirements and strategies to get Gold, see this thread.

NOTE: Since the DLC in this version is part of the main game and not an actual download like on Xbox 360, those missions do count toward this total. You'll probably get four gold going for the "DLC" achievements tied to those sim missions, so you only need to do 8 of the 12 others.