The original game supports WASD and mouselook all the same.
True, it has horribly low sensitivity though, even when it's cranked up to the max.
. Yes, I could just run EDuke, but it will neither work nor look the same.
EDuke is actually pretty much like the original build executable, of course there are differences, tweaks, added options etc. but from what I remember, as long as you don't use the Hi-Res pack, it will at least look pretty much the same.
In addition to that, for any problem with the Build engine and it's games, there is also Ken Silverman's VESA patch: http://advsys.net/ken/build.htm
Well, I guess that doesn't really matter now anyway, since you already have the game up and running properly. But still, if anyone wants to run a Build game (without using DOSBox) that will help.