So I've looking lately for some "old-school FPS" games that used the Build engine, and I came across this game "Witchhaven" which looks something like Hexen, ie Doom-like combat but with fantasy weapons and enemies.

Does anyone know if this game is compatible with any of the Doom source ports like ZDoom?

Witchaven is based on the Build engine, which is the same engine used in Duke Nukem 3D, Blood and Shadow Warrior, so there's no chance it'll work in any of the Doom source ports. And unfortunately, none of the source ports for Duke Nukem or Shadow Warrior works either, since the source code for Witchaven hasn't been released. DOSBox would be your best for playing it on a modern computer these days.

EDIT:
Actually, the source code has been released, but can't find any port.
http://www.dukertcm.com/knowledge-base/downloads-rtcm/src-witchaven-source/

I bought wichthaven II on a flea market recently for 1 euro but had zero luck to get it to work. Then again i suck at dosbox so i haven't taken the time to learn how to install and play a game using the game disk and dosbox. They are really good games though.

The Witchhaven source has been madely freely available by a Capstone programmer on a slightly legally dubious basis, so the groundwork has certainly been laid for a source port.

http://dukertcm.com/knowledge-base/downloads-rtcm/src-witchaven-source/

You'd probably have to ask someone more knowledgeable of the Build engine about how much work it would be to incorporate this into the eDuke32 or XLEngine code to get Witchhaven running.

Edit: Dem ninjas. Give D-Fend Reloaded a crack.

OOOHH awesome!! Thank you!!

Oh right, seems I got things mixed up in my mind. Build is DN3D/SW, Doom is the Doom engine.

If I recall the Capstone games: Witchaven I-II, TekWar, and that unpublished one all used some early version of the Build engine, while DN3D was still in development. But I might be wrong about that. Anyway I doubt there's a source port for any of them, which is kind of a shame, I liked Witchaven.

So it is a DOS game, and not a Windows game?

I think the problem with Witchaven is not that the source release is of dubious legallity, but rather, people who usually do the ports have no interest in porting it.

The same can be said about most of the other Build games actually.

Even Shadow Warrior got only a couple of ports, JonoF's and SWP, and none seem to be actively being developed and bugfixed like eDuke32.

Lucius, the guy behind the XL Engine IS interested in porting Blood, but he's doing it alone and it is low priority compared to Daggerfall and Dark Forces.

Personally, I'd love to have ports for Blood, Witchaven and Powerslave.

Good to know since it's on my play list, and having a 64 bit Windows 7 the most troublesome games to run are old Windows games.