Quackshot had one of the best soundtracks (i m o) for a game on the Megadrive.
Regarding sequals to Castle of Illusion, I think the sequal was called "World of Illusion" starring Mickey & Donald. I just loved when Mickey said;"Alakazaam!!"
I just got hold of the megadrive emulator for Dreamcast and tried it a couple of times. That which made me very happy was that it was virtually perfect graphically and fast, but the sound wasn't as good. It wasn't just the soundeffects that were bad, it was the music too but it varied from time...
I'm also playing PSO, haven't got that far though. Can anyone help me on how to assign other techniques than FOI to the blue button? I just can't get it to work, I have to press Start > technique > and then choose the appropiate one. Sadly the game came without a manual since I bought it secondhand.