HPZ Music

OOZ's beta music is Casino Night Zone act 2.

 

not Casino Night ACT 2 but Casino Night Players, Sonic Chaotix...

 

No real reason to wonder. It just probably wasn't composed yet! Also notice that the beta contains a lot of redundant music tracks; likely these are fillers for other BGMs that aren't in the software yet. (Or until some type of reorganization is performed)

 

  One highly-probable theory on why this is true is because Masato Nakamura(the man from Dreams Come True) had already provided a good piece of music for the Hidden Palace Zone(what turned out to be Mystic Cave Zone 2P vs. Mode's music later), and so, hadn't had need to make -- what, in the end, turned out to be -- Sound Test #010.
  Another interesting tied theory to this is that Sound Test #010 wasn't going to be used for the Hidden Palace Zone at all.  This might explain why the Mystic Cave Zone 2P music is actually in the ending medely music during the credits, but opens another mystery.  Where would it have been used?(Of course, this theory is completely disproven, due to the fact that, through the use of ROM Hacking and/or a 'game enhancement device,' you can access the reminance of the Hidden Palace Zone, and the music played throughout both acts is, indeed, Sound Test #010.)

 

Actually, this doesn't even necessarily disprove it. While it's "very likely", since it's unused and also mapped to the level, there's always the possibility that "music shifting" (where a BGM gets pushed into another "slot" for whatever reason they chose to reorganize) misplaced the song Hidden Palace was supposed to have, and just landed on 10. Of course, that's just a far fetched type of guess. Most likely #10 IS HPZ's music, as HPZ was most definately the longest lasting of all the lost levels as far as information is concerned. I remember when my sister had heard from her friend that a level named "Hidden Palace Zone" was removed from Sonic 2, rumored to be the "best looking and most fun" level... this was way back when Sonic 2 had just been out only a few months. Of course, said friend also described desert landscapes and a little alligator so...

... Actually, now that I think about it, I think I DO remember a "Sega Visions" edition that DID feature the infamous Dust Hill pic with the caption of "Hidden Palace Zone" as part of an ad for Sonic 2...

 

They probully just havent made it yet.