Sonic Remastered (S1 Hack) is a ROM hack, specifically identified as an 'S1 Hack', suggesting modifications to the first Sonic game. This would likely entail updated graphics, perhaps enhanced sound, and almost certainly modified levels and gameplay.  Information about the development team is usually found within the ROM hacking community.  It is not produced by Sega, but instead by independent ROM hackers.

Sonic Remastered (S1 Hack)

Sonic Poopy