So yeah, basically, MUGEN is this cool fighting game. As the name implies, it's like Street Fighter.
It has fully moddable HUDS, characters, stages, etc.
Here, have a
link to a MUGEN modsite.
The controls are fully mappable. I think it's customizable with controllers and joysticks, but I'm not sure.
For the MUGEN game, just search it up on YouTube.