Holy **** that game is awesome. I loved that demo to death... too bad my PC only runs it just above low on 800x600... ah well, that's what overclocking is for, hahaha... that or my CPU and RAM are bottlenecking my 8500GT... hmm....
I don't think you could play that on a card much lower than mine... the minimum requirements were kinda low, lol... I'm thinking 640x480 resolution on low will probably get you like 10fps...