I've never seen a worse implementation of multiplayer in any game I've ever played. My friend and I are both on PC but I'm on GOG and he's on steam. You need to know you're IP address and port number in order to get a private game, so my friend and I tried to plug in our addresses to each other's games and nothing worked. We disabled our firewalls (like a suggestion from THE DEVELOPER'S FORUM recommended) and that didn't work. There are examples online of people doing absurd things like setting up a VPN together in order to play just a game together. We both tried setting up a public lobby just to see if we can see each other in the game and there's nothing. Not even random peoples' lobbies but literally nothing. The game barely pretends to refresh to lobby search and there's no way to access even public lobbies. It's terrible and I can't believe how mismanaged this is. The game? oh yeah its alright, there's better post-apocalyptic games and there's worse ones. But I can't get over the multiplayer being as bad as it is.
