I don't think it's ever happened before. Not even with Super Mario 64 DS or Super Mario Sunshine. NSMBW marks the very first time that I got bored with a Mario game. I loved NSMB on the DS. It's my favorite DS game, still. I got to world 7 in NSMBW, turned the game off, and never turned it on, again. It took me forever to even find the motivation to get that far!
So, I guess my answer is Galaxy. One of the best games I've ever played.








