toxicTom: You can download the offline backup installers through the website.
Hover over your account name, then click "games". You should see your game (Far Cry). Click it, and ignore the big blue button, but click "offline backup installers" below. Download all the installer files and place them in the same directory. When you have everything, start the exe of the installer.
You don't need Galaxy to install and run games (except for some multiplayer games).
Thank you very much for your answer. The reason I wanted to download and play it free of gog galaxy is because the cheats didn't work and I was hoping they would work this way. Unfortunately they still don't but at least now I know how to do this much.