(In reply to acutiator from comment #0)
> I'd like to take a screenshot, but Postal 2 likes to take over my desktop
> and I'm not certain how to rectify this. I can't alt-tab out of Postal 2 to
> take a screenshot and using Steam's screenshot utility, I only get garbled
> output.

You could log in via ssh and get a screenshot using a command line utility, or
you could take a picture of the screen.

Please attach the /var/log/Xorg.0.log file and the output of dmesg and glxinfo.