Erm sorry for laughing its just you payed for a game which is in a early release and is free jmless you want to show suport...
hope its just your drivers good luck
first i didn't payed for the game, i did a donation
second i understand it's in early development, but cost nothing to ask
and my drivers are up to date, and tryed to download older drivers and it still dont work.
** i'm using ati HD 5850 as a graphic card