MasterVG71782 on 14 February 2013
My two rarest platinums are for ModNation Racers (1.94%) and Clash of the Titans (2.00%), with a total of 12 platinums under 5% (including the two above).
I can see ModNation Racers, considering it is one of the biggest grinds I've had in a game (next to something like WKC), but Clash of the Titans isn't that hard and it's not that bad of a game.
