i don't know why it's not on gamespot, but Mugen, is basically a 2D fighting engine, which is available for download all over the internet. you can choose to edit backgrounds, music and even the characters! you can make a fight between spider-man and batman possible, in only a few steps!

anyways, i found about this game recently, while i was on youtube. retro fighting fans..get ready for a blast from the past!

Peace