I was playing LAN with two other people and the first time we managed to get in, but it took very long for us all to synchronize past the training phase and into the Von Braun section.
It takes up to 15 minutes to load up a game.
Is there anything to be done?
I can't solve the problem but I can confirm that the criticisms of multiplayer support are overstated. The day the multiplayer support was released, years ago, I started a co-op game with a friend over a 64k ISDN link, and over several evenings we played the whole game through that way. It was a TON of fun, and worked pretty much fine, in fact I'm not sure I ever finished the game in SP mode. I don't remember any particularly long sync time. Perhaps I'm only remembering the good bits, but if it was many minutes I'm sure we'd not have kept playing.
I'm planning to repeat the experience - although at the moment I can't get the GOG version to run at all, SP or MP ! So as you'd expect there's clearly a number of problems with modern platforms - but if they can be worked round, the MP mode should give you a great time.