One step closer to the Danger Zone....
Got the demo installed, loaded it up with no changes to settings and... it worked! Got into the menu screen. Exited out, compared the settings in the setup program between the demo and the retail game. Everything was the same, but something caught my eye! The Memory tab had graphics memory set to 19 on the retail and 11.4 on the Demo!
So I set that to 11.4 and the loading screen appeared! Then some hard drive light activity, and then it froze

So a little closer to being able to play it.
Tried to enable Warp3D and it didn't even get to the loading screen. Time to investigate that, because I don't think I've had anything except the Heretic II demo work with that yet. Any recommendations on a game or demo that uses it?