Sonic the Hedgehog (Prototype) - Hidden Palace

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

SEGA Sonic the Hedgehog Prototype Game Build from 1991 Surfaces, Here's a First Look - TechEBlog

Sonic Prototypes (released by Hidden Palace), Page 2

Long-lost level restored in Sonic the Hedgehog 2 remaster

Dreams Come True: Sonic 1 (MD) Prototype (Hidden Palace) : r/SonicTheHedgehog

Sega Genesis / 32X - Sonic the Hedgehog 2 (Prototypes) - The Spriters Resource

Lost Hidden Palace Zone (Classic/Rem [Sonic Mania] [Works In Progress]

Stream Hidden Palace Zone (Prototype Version) by Sonic's Music Collection

Concepts and prototypes, THE Sonic the hedgehog Wiki

SegaPede BG for HPZ. [Sonic The Hedgehog 2 Absolute] [Mods]

Sonic the Hedgehog 2 (Sep 14, 1992 prototype) - Hidden Palace

Sega Genesis / 32X - Sonic the Hedgehog 2 (Prototypes) - Hidden Palace Zone (Dry) - The Spriters Resource

Proto Palace Zone, Sonic Wiki Zone

Hidden Palace Zone - Sonic Retro

Sonic CD - Wikipedia