I just found out that Viscrera cleanup detail: shadow warrior is supposed to have multiplayer. After doing some research i have determined that the version of the game is not up to date. The current gog version is 0.20 while the main version found on steam or from the sight is on 0.28 . I do not know if this will be fixed in the future. I for one would like to ask gog to please update the game and possibly allow us to play it together.

yeah, I contacted devs a long while ago (in June 2014), they promised to update game on GoG, but nothing yet... So I guess we are out of luck...