Penumbra Overture Could not set displaymode

[Yuhaney]

Might be that Penumbra: Overture doesn't support your resolution.
However, you can go to the games folder and find file called settings.cfg and open it into notepad and then set the resolution you want manually.

In this case, it would be:
Screen Width="1680" Height="1050"

Also, make sure that you check the fullscreen from there!
If it says FullScreen="false", set it to FullScreen="true".
Save the file and run the game.