After the game is redownloaded, before you run it, it might also help to let the game recreate the settings and profiles. That can be done by renaming the folder Amnesia at Documents to Amnesia_OLD(don't delete it because your saves are in there! If the game is fixed we will move them afterwards. Unless you don't have any saves, in that case delete it).
I deleted the Amnesia folder, the save files weren't important and this way I know it was a 100% fresh installation.
The game is running perfectly on the same settings now, although I checked the log after closing the game and strangely I'm still getting a lot of the same errors. I suppose it doesn't really matter though as it hasn't caused me any problems yet, thanks again for your help!
My God this game is scary when it runs properly! D:
Great, have fun playing the game.
Steam seams to be corrupting the game lately...