HunchBluntley: Read the release thread, dude. The devs have posted there.
Also, this is hardly the first game on GOG that's had the mutliplayer stripped out to be released here.
I do agree that they should have a prominent notice about its absence on the game page, though.
paladin181: It's not in the release post, but some replies to it made later. It still sucks when that was part of the reason I bought the game. The dev said we get the full Redout experience at a discounted price, but without multiplayer that's not quite true. I'm just pissed I lost my money on something that's now worthless to me.
It definitely could have been handled better (by GOG, as well as the devs). But I still don't fault the developers for the decision to not go to all the trouble of porting the Steam-based multiplayer to Galaxy when they aren't sure if the game will even sell well enough here to pay for the time spent reworking it.
I'd still contact Support and see about a refund, even though you've already downloaded it. They've made plenty of exceptions to their general return policy in the past.