http://www.hidden-palace.org/
http://forums.sonicretro.org/index.ph...
This is footage to show off the differences in the 0517 beta of Sonic the Hedgehog 3C's Hidden Palace Zone.
Differences of note include music (level music uses Sky Sanctuary's BGM, and the miniboss music plays compared to the Knuckles theme), the first shield to the right of the transporter, the fact that Knuckles breaks the wall THEN urges Sonic over, and the fact that when Eggman appears to steal the Master Emerald, you're unable to move.
Also worth noting is that if you attempt to escape from the control lock using debug mode, Eggman cannot be attacked - you'll go right through him.