Will continue to investigate and I'll report back any progress I make here. Surely this game wouldn't be dumb enough to only allow 1 person of a particular Windows username to join a local server?) this is the Windows username on both PCs. (Actually, a thought just occurred to me. The player username (shown in the UI) for both PCs is 'User', and I don't know how to change it in-game. When another PC attempts to connect to my LAN server, it gets an error ' Already logged in. I've encountered a showstopper problem, and ended up here in the hope of finding a solution, because googling isn't turning up anything helpful.
' I bought the game yesterday specifically for this feature, and yes, there does seem to be a local LAN play option - I can create a server, add bots, and the server is visible to other machines on my LAN.
Tfishell: I don't know personally, but the top review claims ' There is a LAN option available.