According to jq,net, a fan-made 8-bit nes Doom style shooter as been made.
Yes, Mega Man shoots, and ooohhhh yeah, he shoots a hell lot. But despite being a vanguard for 2D sidescrolling shooters in the 80s, you can't help but wonder what the game would be like if it went the path of Doom. Fortunately, there's a fan-made project that fills that void - here it is: Mega Man 8-Bit Deathmatch.
via CutStuffMega Man 8-Bit Deathmatch is an on-going project by its lead developer, CutmanMike, who aims to turn this mod into a fully-playable online multiplayer game. Judging by the video, there will be multiple characters, different weapons, and even varying environments. How awesome is that? It's still a work in progress, but it looks fantastic, pixels and all.