M.U.G.E.N
M. U. G. E. N is a free program for making fighting games. It works on old computers and Linux. It's like a magical box for game creators.
I used Linux to run M. U. G. E. N. It felt like magic.
My grandma plays M. U. G. E. N on her old computer. She's a beast.
I made a whole game with it. It's a miracle.