I’m playing it right now, amongst my regular gaming time… between matches of Starcraft II and trying to wrap up Red Dead Redemption before the fall downpour occurs. There’s a caveat though, which is that I’ve played a lot of this game. I’m going to try to tell you why this is the case. Maybe Super Metroid comes close but I like to think of that less as a platformer than a shooter/puzzler. Even if you count in the Donkey Kong Country series, Yoshi’s Island still comes out on top. I haven’t played much of Galaxy so I’m not super qualified to comment there, but I’ve played an awful lot of Mario and Mario derivatives over the years and I’m definitely not afraid to suggest that Yoshi’s Island is in the top three all-time Mario-related games. The camera alone disqualifies it (and arguably any other 3D attempt).
Super Mario World 2: Yoshi’s Island is the best platformer Nintendo released until New Super Mario Brothers Wii.