I have no idea what's causing these problems, and it might even be as simple as my game's graphics settings, though I haven't had time to mess around with them yet. Any help is greatly appreciated!
I think updating the drivers for the graphics card will solve this, if not I think you can turn off bloom (or it might be some other effect) in the graphics options to get rid of it.
My graphics card is up to date, and I'm still having the issue. It is a semi-old card, though, and I don't think it's being manufactured anymore. Still, Overture and Black Plague, as well as Amnesia, all worked fine.
Also, if it helps, here is a screenshot of my current graphics settings. I don't see any bloom option, and the rest of the settings are set the same as I have them in Overture and Black Plague. http://dl.dropbox.com/u/2780202/requiem_...-24-46.png