We were running the game on this:
Athlon 2400 XP
Gainward Geforce 4 4600 Ti PowerPack Ultra/750XP
Audigy with 4 Speaker Setup
MSXML 4.0 Parser installed Download it here
Windows XP/2000 are the only tested platforms
We have run it on less powerful systems, but since shadow volumes are rather processor intensive (due to running in software as opposed to the GPU), this kind of system can run it well.