At least it started for you, true Im usign the Demo 2 and not the GOG release, but if I select 1600x1200 in the options it just says my 24" monitor doesnt support that resolution and quits.
h0w1ers tip helps, cheers, but having to run it in unvolentary window mode feels a bit so so.
im going to assume that the 24" monitor is supposed to display 1600x1200 right?
ps. h0w1er's solution works. but its a bordered window and a few pixels on the sides of the screen are cut off as a result.
not ideal but it is a solution.
i myself will stick with the ingame resolution i think because i hate seeing the window borders on screen, very distracting.