Halo 1 is DirectX8, so unfortunately it won’t work for the first release version (might change in the future), but I will look into Halo 2, which uses DX9, I believe. No promises though. ;)
I played Halo 2 last night with a Halo 1 profile i found in the VorpX cloud. Worked fine and fluent with geometry3D. Though i must state the monsters look quite pixely compared to 3D Vision, but thats normal in VR i guess.
BTW: If vorpX would allow DX wrappers like DGVoodoo taking place in the game folder, DX8 and lower games like Halo 1 could be played.