Assassin’s Creed 2 (360)
Since I was so close to getting all the achievements in the game, I went back and, er, got all the achievements. Collecting all the feathers was the real time consumer, especially since I only had 30 or so of the 100, and after that I just had to wear my prize in all the game locations (easy) and perform a few fancy fighting moves for the remaining achievements. And that’s it! I could go and get all the treasures …