update 5/14/16: Found this while looking to see if we had a thread for Doom 2016. In this thread I was talking about Doom 64 Absolution, which was a total conversion for Doomsday. He basically remade he game. The creator has long since released Doom 64 EX, which actually uses the original Doom 64 data, and requires an N64 ROM file. You can get it here:
https://doom64ex.wordpress.com/downloads/ but you'll need to place a Doom64 rom file in the folder and run Wadgen.exe to get it to create the data files needed to run.
Original post:
I remembered this when reading Cobra's thread about Doom+Heretic+Hexen flash. This may be old news, but someone ported Doom 64 (more like recreated I think) on the Doomsday engine. I used to own Doom 64, and so far this seems like an excellent recreation.
I'm sure there's a certain amount of hate for Doom 64, since it wasn't created by id (I don't think), it was a console exclusive, and it didn't add all that much to the game series despite the progress of FPS at the time. However, it's a slightly prettier version of Doom with different levels. Plus it's got a double bladed chainsaw!
http://www.doom2.net/~doomdepot/abs-download.html