Hidden Palace Zone

Located on West Side Island

Sonic the Hedgehog 2 (16-bit) - Hidden Palace Zone
The zone begins with the player character falling through the pit, similar to the intro of Lava Reef Zone in Sonic & Knuckles. It is an underground cavern full of water featuring sparkling gems and rocky regal structures, possibly ruins of some ancient civilisation.

In addition to some familiar features, there are objects not previously seen in any version of the game, such as a jellyfish-type Badnik that acts similar to Grabber, fully functional water slides, the unscalable diagonal tunnels given a propelled zipline device, spikey mines that are swung back and forth and a unique Dr. Robotnik boss fight (dubbed Brass Eggman) involving musical instruments, explosive debris and water.

Nearby

 * Mystic Cave Zone - Sonic the Hedgehog 2 (16-bit) (accessible via secret passage)
 * Oil Ocean Zone - Sonic the Hedgehog 2 (16-bit)