Nostalgic FPS Engine Thread

I'm looking for an engine that develops nostalgic first person shooter games, games like Doom, Wolfenstein, and Star Wars: Dark Forces. The ones with sprites that are 2D and change due to the perspective you're looking at them from. To my surprise, I couldn't find any engines of old 90's FPSs or new nostalgic FPS engines. Does anyone know of any of these engines that are still available for use? I'm looking to potentially make indie games using them.
Thanks,
MW

I believe that id Software released their engines, but as far as I know they're commercial, not free. You could also program your own engine, but that would be a lot of work.

Could you possibly provide a link? Like I said, I looked but couldn't find anything.

And I'd really like to get my hands on the jedi engine, the one used to make Star Wars: Dark Forces. It has the same capabilities as ID Tech 1, the Doom engine, but with Z plane capability, or vertical capability, allowing several floors and going up and down, plus crouching and jumping. I found a modding tool (http://www.df-21.net/downloads/utilities.html), but it's outdated and doesn't run anymore on my modern mac.

Zdoom is one: Zdoom.org

Just do a yahoo search for "doom gpl" and you'll find several ports that let you do things the "old" way or more modernized.

Thanks Happy -- this is exactly what I was looking for. But could anyone find this for the jedi engine?

if you can work it you can try the early access of my engine here is a demo link: Copy.com, PM me for source code

The link doesn't work...

try this one: Copy.com