From another topic:

Originally Posted by Lar_q
*Currently* the PC version supports both PC & Xbox360 interfaces (they are quite different from each other). We still need to figure out if we'll support games for windows and if we do, that means we'll need to ship with controller support (as it's one of the requirements). The press demonstration happened with a 360 controller because we were just in the process of implementing the PC interface. The presentation at Leipzig will be using the PC interface.

Sektor followed up that post with a wikipedia link about the 'games for windows' program.