[quote=@Gentlemanvaultboy]
I think of the fighting game engine. 
[/quote]

Especially with the whole thing about "The Balance" that keeps the realms from crossing over, and the hilarity of using M.U.G.E.N. to basically throw people from different realms (using our game terminology) at one another to see who wins. This is either a happy coincidence or a stroke of genius.