A few years back, someone made a free beat-em-up called Beats of Rage, which put SNK King of Fighters characters in Sega's Streets of Rage game. The makers then released an editor that allowed anyone to use the BoR engine to make their own mods, including this GI Joe version:
That's outstanding! Some of the choices are weird (Why does Hawk take off his jacket? Why is his walk animation so weird?) and there are some flaws, but if this had come out for real in the '90s? We would have been all over it!
Sadly, the link provided on that video page to download the game seems to be dead. However, this link is currently working, and shows that the game was expanded with new characters and new levels just this year. Download it and give it a play!