Sonic the Hedgehog CD (Aug 1, 1993 prototype) refers to a prototype version of Sonic CD from its development phase. This is a pre-release build of the game, meaning it contains unfinished elements, potential bugs, and variations from the final product.  It provides a glimpse into the game's evolution and gives insight into the development process.  Gameplay would share similarities with the released version but possibly feature differences in levels, music, and overall mechanics.

Sonic the Hedgehog CD (Aug 1, 1993 prototype)

Sonic for MegaCD