To play this game online with a friend, you first need to create an account (for some reason). A 'GoG-Staff edit' in an earlier review, claimed the serial key would be for the multiplayer portion of the game and could be used as many times as needed. This is untrue! My brother created an account using the serial key. After that, my attempts to create another account failed with message, that the entered serial key was already used to create an account. My brother is currently attempting to contact GoG.com support to request a second multiplayer serial key. Until then, my rating will remain 1 star. If you want to play online with friends, i would recommend sticking to Steam and getting a 2-pack, unless you want extra hassle. I would guess joining a friend's game is also easier on steam.
