Just had opportunity to check it, and multiplayer works without need for Galaxy nor steam. There seems to be buit-in server search in game, LAN works too.

Sadly, no co-op mode for campaign, nor ship battles in multiplayer - it is all land-based battles (including interesting modes like conquest or hunger games). No chances for finding people to play with randomly, though, so if planning to play MP, better have friends arranged in beforehand.

// Edit

And no, game isn't abandoned here - currently, GOG version is updated to latest. Albeit, I must add that delay in bringing some updates was, indeed, of absolutely unacceptable magnitude.