It seems that you're using an outdated browser. Some things may not work as they should (or don't work at all).
We suggest you upgrade newer and better browser like: Chrome, Firefox, Internet Explorer or Opera

The store page does not mention if LAN is a working feature with or without Galaxy and I would appreciate a confirmation that this game has the LAN feature fully accessible in either case.
This question / problem has been solved by QWEEDDYZimage
I sure this already asked here.
Offline and Galaxy use differ build. First based on LAN\GameSpy 1.1 version and 100% have LAN TCP\IP features.

In Steam\GOG Galaxy you can create new MP game from multiplayer menu. Dont remember about Internet\LAN switcher...