The prototype of Hidden Palace. The level never made it to the cartridge. Did I mention the glitches I ran into while I recorded this?
Glitches:
-The music from the 2-Player Mystic Cave level plays during thw whole level.
-When you start to drown in the water with the drowning timer counting down, the Level Select music plays instead.
-Jumping out of the water when drowing makes the Emerald Hill music play.
-When being invincible in the water and starting to drown, jump out of the water and the Aquatic Ruin music will play. Once the invincibility runs out, the 2-Player Mystic Cave music will play again!
-Their is a Tails' 1-Up Monitor instead of Sonic's.
-The level might of had the layout of the Metropolis level, meaning when you fall, you fall forever, never falling off the screen.
-Collecting 100 rings in the level triggers the Death Egg Music to play.
-Tails is missing his braking sprite when he stops suddenly.
-The tubes don't make you spin like you spin in the Casino Night or Hill Top level.