Now this is fascinating. The Super Mario Bros 2 that came out in the US is actually not the real Mario 2. Nintendo thought the real one was too hard, so they modified another game called Doki Doki Panic with Mario graphics and released that instead. That explains why Mario 2 is kind of the odd man out among the whole series, with its weird gameplay mechanics (Pulling turnips out of the ground? What the fuck is that?).