Sonic Genesis for Master System is a platform game for the Sega Master System. It was released in 1991 in Europe and Brazil.  The game features Sonic the Hedgehog and his sidekick Tails as they race through various zones to stop Dr. Robotnik. While not an official Sega release, it's considered a significant fan-made title and is notable for bringing the Sonic experience closer to the Genesis style to the Sega Master System.

Sonic Genesis for Master System

Sonic Blast (Brazil)