janjitse: Hi, bought the game (on Thursday of course), but it won't start, some sort of DirectX error: Failed to initialize Direct3D, make you sure you have DirectX 9 installed, and something about Pixel Shader 1.1.

Crash reporter also sent a report to the devs.

System: Windows 8.1 64-bit, Radeon R9 280, 16GB RAM, Intel Core i5 4690.

The demo from Steam gives the same error.

Does anybody know a solution?

Never mind, followed the instructions on the steam forums (but cannot post any links now?).

and fixed it (for the record, the solution was deleting the prefs.cs file).
Maybe put this in a sticky here too?
Anyway, happy I can play the game now.