Unreal; and later, Deus Ex, based on Unreal too :D.

But Windows 2000 was much better for gaming. NT4 supported DX3 and DX5 unnoficially'.

W2k had a DLL call flag to enable a Windows XP like compat mode:

http://www.activewin.com/tips/win2000/1/2000_tips_43.shtml

It only worked on desktop shortcuts, but enough to run most quirky Win95/98 games.

I think Unreal Tournament ran on NT4 as well.

Despite Win2k and NT4 kinda having a rep for not for gaming, I found that most games actually did run on them fine. Especially Win2k, probably the most underrated OS of all time in the Windows lineup.

Really I think it got that rep mostly from people trying to run DOS games or shoddy ports from DOS to early Windows that still relied on a bunch of DOS stuff.

I always suspected Microsoft tried to market it as such otherwise their Windows ME (remember that sh1t?) wouldn't sell...

win2k's support for games was miles ahead of NT4 because of DX 8.1? support. If not DX8, DX7 0a was for sure supported.