Anyway, someone's created a Mega Man mod for Doom, and it looks pretty neat:
"Megaman 8-bit Deathmatch is a new multiplayer mod that aims to puts Doom and Megaman into a blender and spew out a fun new way to blast your buddies online.
"Megaman 8-bit Deathmatch will play as if Megaman suddenly turned 3D. Everything will play as if it was being played back in 1987. Levels will use purely 8-bit textures and sprites. Megaman will jump high and take damage recoil. Weapons will behave exactly as they did back then, only from a 3d perspective. The plan is to eventually have all the levels and weapons from Megaman 1-6 (and maybe 9). Obviously some weapons will have minor changes because there are a lot of clones throughout the series."
The alpha build can already be downloaded: http://cutstuff.net/blog/?p=1677
