I recently picket up the first game on a sale ant have just started to play the main campaign, but I'm having a small problem with the resolution.
If I put it on 1920x1080 everything becomes to small and I can't read anything, so I bumped it down a few pegs to a resolution that fit my monitor.
The problem I'm having is that the resolution effects things outside of the game, so when I try to tab out of the game everything gets down-scaled and the windows become small, I also can't tab into the game again because the image gets super corrupted.
Is there any way to set the resolution to something where I can see whats going on, but it also not affecting things outside of the game?

I use DgVoodoo myself to get correct aspect ratio.
I run the game in 800x600 and Alt-Tabbing is no problem.

Hmm, ok. From my googleing I've come to understand that it is some kind of third party program. Is that right? And does it work if I launch from GOG Galaxy?

Yes, it's a third party program.
No idea if it works with Gakaxy, but I don't see why it shouldn't,

If you select "allow resolution changes" you can make these shifts without having to change your desktop resolution. Alt-tab is your friend in this case.

Sometimes resolution can be troublesome when you prefer one resolution on the main menu screen and a different resolution during games.