Sonic the Hedgehog (Prototype) - Hidden Palace

A prototype of Sonic the Hedgehog for the Sega Mega Drive.

A brief history of Sonic The Hedgehog on PC

Segapede prototype released!

How to Unlock the Hidden Palace Zone in Sonic Origins - Prima Games

Sonic the Hedgehog 3 (Nov 3, 1993 prototype) - Hidden Palace

Sonic Origins tech review: glitches and a steep price make for a tough sell

Sonic the Hedgehog 2's Proto Palace Level Discovered: How to Unlock it, with Hands-On Video

Sonic the Hedgehog (Prototype) - Hidden Palace

New Sonic the Hedgehog (1991) prototype uncovered by preservation groups - Tails' Channel

Hidden Palace Zone in Sonic 2 Master System! by ThomasTheHedgehog888 on DeviantArt

A story that gave a developer a pirated version of Sonic the Hedgehog 2 to developer Yuji Naka - GIGAZINE

Alexander1987: Sonic 2 beta ( Delta ) with clocker woods, hidden palace, and sand zone, deleted stages from sonic team 1991.

Sonic the Hedgehog 2 - Hidden Palace Zone by SonicDash57 on DeviantArt

Sonic the Hedgehog 2 (Genesis) - The Cutting Room Floor

Sonic the Hedgehog (Prototype) - Hidden Palace

The Sonic & Knuckles beta cartridge shows truly what SEGA is doing. They want Sonic to be more than an icon. If he's in our reality, fun will TRUELY be infinite. Don't