Because M.U.G.E.N is typically a standalone PC application (.exe), it is often blocked by administrative firewalls or restricted from being installed on shared computers. Users employ several methods to play "unblocked":

refers to methods and platforms that allow users to access the highly customizable M.U.G.E.N fighting game engine in restricted environments like schools or workplaces. Originally developed by Elecbyte in 1999, M.U.G.E.N (Japanese for "infinite") is a freeware engine that lets players build their own 2D fighting games by adding custom characters, stages, and music. What is Mugen?

: You can pit Goku against Superman or Mario against Scorpion by downloading individual character files.