Thank you all for sharing this. I have never used Hex Editor before but following your instructions I managed to switch the resolution to 1920x1080.

One more proof that GOG community is the best

Here

i tested it and it does not run in full hd. it runs in 1024x768. it did however fix the problem with the intro not rendering and the fact that i had to minimise the game in order for it to render. at least it fixed that.

after testing it i found a critical bug in multiplayer. multiplayer crash after a while with true virtual function call.
i found another issue however: the edited executable can not be removed.

This method worked fine for me. Game runs in 1920x1080. I didn't try multiplayer though.