Without much if anything in the way of advance notice, Prison Architect has rolled out the early stages of an online multiplayer. While not a full launch, you do need to opt into the Alpha / Beta options with Steam. Once you have made those changes, you can build your prison with up to 7 online friends. For more information, head on over the update section via Steam.
While there’s plenty aspects of the game missing from the multiplayer, Introversion is looking to update the game if this option proves popular. If not, well the team behind it probably wont put too much effort into doing so.
This sentiment comes from the recently posted video where the Introversion founders discuss the update. You can see that video below where co-founder Mark Morris says “This is really for the brave to go in at the moment”.