The 8-bit Sonic the Hedgehog 2 for Master System and Game Gear was developed by Aspect Co.
Released in 1992, this version was a separate game from the better-known Sonic the Hedgehog 2 made for the Sega Genesis. Although both titles share a name and arrived around the same period, they have different level designs, music, and stories. The 8-bit game follows Sonic as he tries to rescue the kidnapped Miles “Tails” Prower.
Aspect developed the game with cooperation from Sega. It was not a port of the Genesis release, and the Aspect team did not work directly with the Sega Technical Institute team developing the 16-bit version.
A frequent mix-up involves Ancient, which developed the first 8-bit Sonic game in 1991. Aspect took over development for Sonic 2 and later handled several subsequent 8-bit Sonic titles.