For myself and others at the link below, the maximum resolution selectable for the game is 1440 x 900 rather than the desired 1920 x 1200. Editing the .ini file has no effect, with it defaulting to 800 x 600 or some low resolution like this. I can't find any solutions to this problem online with most people's response being to simply choose it from the Options menu as the problem is not present in their version.

I have the GOG version, acquired during the sale and it's version 1.64.

http://www.wsgf.org/forum/forums/gaming/detailed-widescreen-reports/6410/painkiller-detailed-report?page=2

This does indeed sound weird. What are your system specs? And if you have a reasonably fast internet connection have you tried re-downloading and installing?

System specs are a bit old:

Dell XPS Gen 2 Laptop
Pentium M 2.0 Ghz
nVidia Geforce Go 6800 Ultra 256mb
2GB RAM
Windows XP Pro Service Pack 3

I haven't tried reinstalling, but don't really see how that would effect it other than resetting the .ini files. It might be a video driver issue of some kind, but I've been playing at the lowered resolution rather than mess with it any further.

I have a non-GOG version of Painkiller Black but mine goes up to 1920*1080 in the standard video options, so seems odd that you don't have the same options.

For me the resolution setting was messed up as well, with maximum selectable being something like 484x480. I got my version off Steam. I discovered a forum where someone suggested disabling/uninstalling monitor software. For me it was fortemanager from LG. I uninstalled it and now I can select my monitor's native resolution.