However, it also allows players to create their own M.U.G.E.N. Most of the game’s versions employ the standard arcade control layout, with directional and action keys. For casual users, the main app is a 2D retro fighting game that mashes different characters, such as Super Mario’s Peach fighting with Chun Li from Street Fighter. engine is written using the C language and was originally built with the Allegro library, later replaced by SDL libraries.