One is based on the original and one is a (more modern sounding) non-copyright infringing derivative. http://www.youtube.com/watch?v=qaC0vNLdLvY
The unused Sonic track doesn't fit Sonic at all IMO, it sounds like it would be better in a RPG. :v: It's still a great track regardless though!
The unused tune sounds almost like a successor to Marble Zone. It would fit fairly well in a more carefully-traversed zone, such as a castle or fortress. I am so glad this came to light. It is an enjoyable song, and now has me wondering if Sonic 2 would have been received differently had the music gone in this direction instead.
Wasn't there a level named Madness Mountain or some such that came out from the Cook and Becker art book that was a development idea from Sonic 2 that was along the idea of a Castle looking Zone/Marble Zone? Maybe some of the tracks date back to some of the earliest concept art thinking of the idea of zone follow ups.
This is interesting: http://youtu.be/YSmBDejexpg Things still point towards him being the one in charge of temporary music. EDIT: That title music is still in the game, by the way: https://tcrf.net/Dr._Robotnik%27s_Mean_Bean_Machine_(Genesis)#Unused_Music
Assuming this really was for Sonic 2 and wasn't mislabelled or anything, I know that Casino Night was going to be a part of a dystopian future (this was when Sonic 2 still had time travel in it), and judging from the name "Club Scene" and that it sounds kinda sinister, maybe this was meant to be for Casino Night? Or a cutscene related to it?
http://www.youtube.com/watch?v=2BWKWjh0Pgc http://www.youtube.com/watch?v=bu55q_3YtOY Oh dear oh dear. David Javelosa seems to be getting the credit in Dr. Robotnik's Mean Bean Machine for (presumably) the new tunes.
If I was a betting man I'd guess that his tracks weren't ever set in stone for anything, rather a few conceptual tracks made for a number of different scenarios. Cause let's be real here I don't thin sonic team would publish many STI tracks in one of their games given the harsher and less "soundtrack-Y" sounds that usually come from that department. Remember, SoJ and SoA had very different perceptions of the character and the world he comes from.
Interesting that the music isn't just the change in this Mean Bean Machine prototype; sprites for Robotnik laughing don't exist at this point either, he just stomps and rages like earlier. Drums are also different.
Hey, #6 in the Ecco 2 bank was used in the SEGA Channel menus: http://youtu.be/sRJ8D0w0g4o?t=580 (9:40)