| Game Gear/Master System Titles: Sonic Blast Prereleases (Game Gear) | Sonic Drift (demo) (Game Gear) | Sonic Spinball (8-bit) Prereleases (Game Gear) | Sonic the Hedgehog (Game Gear prototype) (Game Gear) | Sonic Triple Trouble Prereleases (Game Gear)
Mega Drive/Mega CD/32X Titles: Dr. Robotnik's Mean Bean Machine (prototype) (Mega Drive) | Knuckles in Sonic 2 Prereleases (Mega Drive) | Knuckles' Chaotix Prereleases (32X) | Sonic & Knuckles Prereleases (Mega Drive) | Sonic Spinball (16-bit prototype) (Mega Drive) | Sonic 2 (16-bit) Prereleases (Mega Drive) | Sonic 3D (16-bit) Prereleases (Mega Drive) | Sonic the Hedgehog 3 Prereleases (Mega Drive) | Sonic the Hedgehog CD Prereleases (Mega CD)
Pico Titles: Sonic the Hedgehog's Gameworld (4 prototypes) | Tails and the Music Maker (8 prototypes)
Saturn Titles: Sonic 3D (Saturn tech demo) | Sonic R Prereleases
Dreamcast Titles: Sonic Adventure Prereleases | Sonic Adventure 2 Prereleases
Other Titles: SegaSonic the Hedgehog (revision A) (Arcade) | Sonic Advance 3 (prototype) (Gameboy Advance) | Sonic Heroes (Xbox E3 version) (Xbox) | Sonic Heroes (GameCube) Prereleases (Gamecube) | Sonic Mega Collection (prototype) (GameCube) | Sonic N (prototype) (N-Gage) | Sonic Rush (E3 beta) (Nintendo DS) | Sonic the Hedgehog Pocket Adventure: Trial (NeoGeo Pocket)
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