Super Sonic Galaxy 2?

[Omegajak]

That's why I always figured they'd be in a game that was different from their usual play type. One time I came up with a side scrolling beat 'em up starring the two. Come on you know you'd love it.

Yes and the bonus levels could be like:

I thought the Sonic Adventure games already taught us about being able to have different gameplay types over the same levels

Like, say, for one given level, Sonic will get the massive twisted part to complete since he could fly through it
while Mario gets the high-jumping precision platforming shortcuts of the level

Oh wow, look at that we just made the ground work for a possibly great Wii exclusive imagine that. High Five anyone? Anyone?