I've talked to a few people and they tell me gaming on the mac is horrible, I believe them Assian's Creed 2 is now playable with anyone that has the 330m GT graphics card.
EDIT:
And for anyone wondering, here's the full is of games for the Mac- http://en.wikipedia.org/wiki/List_of_Macintosh_games
EDIT:
And for anyone wondering, here's the full is of games for the Mac- http://en.wikipedia.org/wiki/List_of_Macintosh_games