Sonic the Hedgehog (Japan, Korea) [Hack by Esrael+Yuski the Dog v0.40] (~Sonic Gaiden) is a ROM hack that incorporates elements from the Japanese and Korean versions of the original Sega Genesis game. Developed by Esrael and Yuski the Dog, this ROM hack, labeled ~Sonic Gaiden, likely implements substantial modifications.  The gameplay would center around platforming, but with potentially altered levels, graphics, or gameplay mechanics. The creators are explicitly mentioned, offering a clear origin point compared to many other undocumented ROM hacks.

Sonic the Hedgehog (Japan, Korea) [Hack by Esrael+Yuski the Dog v0.40] (~Sonic Gaiden)

Sonic the Hedgehog - Tisha Mania