Sonic Chaos (May 17, 1993 prototype) - Hidden Palace

A prototype of Sonic Chaos (also known as Sonic & Tails in Japan) for the Sega Game Gear.

Sonic Chaos (Jun 30, 1993 prototype) - Hidden Palace

Sonic Prototypes (released by Hidden Palace)

Sonic the Hedgehog 2 - VGFacts

Mean - Machines - SEGA - oct 1993

Early Sonic 3 prototype found, features major differences to the

Sonic Origins Plus (Nintendo Switch)- Review – Seafoam Gaming

Doctor Eggman, Sonic Wiki Zone

Sonic The Hedgehog Series (Alternate Timeline)

Sonic Hacking Contest :: The SHC2022 Contest :: Sonic the Hedgehog

Proto:Sonic Chaos (Game Gear)/May 17, 1993 - The Cutting Room Floor