Sonic Remastered Final Version (S1 Hack) suggests a completed version of a previous ROM hack. It's an iteration of a Sonic the Hedgehog ROM hack, focusing on visual and gameplay improvements.  As an 'S1 Hack', it primarily works on modifying the first Sonic game.  Details on its development are likely available through Sonic ROM hacking communities, but it's not an officially supported Sega product.

Sonic Remastered Final Version (S1 Hack)

Sonic Primo (SHC 2023 Demo)