Super Sonic (lost build of cancelled Sega CD port of Sega Genesis platformer Sonic the Hedgehog 2; existence unconfirmed; 1992-1993) - The Lost Media Wiki

Sonic the Hedgehog 2, Sonic Wiki Zone

Sonic the Hedgehog (lost build of cancelled Amiga port of Sega Genesis platformer; 1992) - The Lost Media Wiki

Sonic the Hedgehog 2, Sonic Wiki Zone

How Many Ports of Sonic 2 (1992) Exist? - Sonic The Hedgehog 2 Release History

Editing Sonic & Sega All-Stars Racing (lost prototype builds of multiplatform racing game; late-2000s) - The Lost Media Wiki

Sonic the Hedgehog (lost build of cancelled Amiga port of Sega Genesis platformer; 1992) - The Lost Media Wiki

Reviews: Sonic the Hedgehog 2 - IMDb

Super Sonic (lost build of cancelled Sega CD port of Sega Genesis platformer Sonic the Hedgehog 2; existence unconfirmed; 1992-1993) - The Lost Media Wiki

Editing Sonic The Hedgehog 3 & Knuckles (lost build of cancelled iOS port of Sega Genesis platformers; 2014) - The Lost Media Wiki

SegaSonic the Hedgehog (lost build of cancelled 32X port of arcade platformer; existence unconfirmed; 1994) - The Lost Media Wiki

CryptoPunkets #891 - CryptoPunkets

Super Sonic (lost build of cancelled Sega CD port of Sega Genesis platformer Sonic the Hedgehog 2; existence unconfirmed; 1992-1993) - The Lost Media Wiki

Sonic Saturn (lost build of cancelled Sega Saturn prototype of platformer; mid-1990s) - The Lost Media Wiki