I'd like to add that the Dreamcast port barely worked at all. I still have a disc with SRB2 v1.09 beta on it for Dreamcast. There's no music, all the SFX are messed up, and the framerate isn't all that great either.
So yeah, there's technically a Dreamcast port of SRB2, but I don't see why anyone would want to play it other than the novelty of it.