If I may play Mr Correction, I'd like to point out that Bit.Trip Runner is actually available on Steam - £6.99, the UK store says.
On the topic of Super Mario Sunshine, I think that it's a similar case to Zelda: Twilight Princess. The game's critical reception back at its release was, in fact, very positive, and I get the impression that the people who lob unkind comments at Sunshine nowadays have a warped memory of the game and really ought to replay it.
And now for some unrelated trivia: I hear that the remixed music for Cave Story 3D is being done by Super Meat Boy composer Danny Baranowsky. I don't know if that will ultimately be enough to persuade me, but it's most definitely a factor in favour of Cave Story. Super Meat Boy's music is magnifico.