M.U.G.E.N. (or simply known as MUGEN) is a modifiable 2D fighting game engine that was created by Elecbyte and initially released in 1999. It was programmed in C, which was originally used in Allegro library, and it compared to 5 versions: DOS MUGEN, Winmugen, Linux Mugen, Mugen 1.0 and Mugen 1.1 as the latest release.