I have been working on a Quake-like engine for over a year now.
This uses it.
It is currently just a short demo.
It should run in MS-DOS or Win32.
You can't save the game, the load menu is a dummy one.
There isn't much to do other than walk around.
There is more art than was possible to include, in the end.
You could see it with Misfit Model 3D.
all3d.cfg can be edited, to change resolution, bitdepth, enable or disable lights.