Everyone knows that creating a video-game is a long, arduous process. Down the road, many games undergo such drastic changes, that they are virtually indistinguishable from different builds. Such is the case with the Sonic 2 Betas. I say 'betas' because the online community has in fact discovered seven different in-production copies of Sonic 2, each giving us unique insight into director Yuji Naka's vision of Sonic 2.
Be sure to check out my full write-up on the Betas here
at Hidden Gems, which includes links for further information, and how to obtain the prototypes yourself.