Big Ambitions Multiplayer Mod: Going Public Setup & Co-op

Install one copy of Going Public

On Windows, update Big Ambitions before installing the mod. Version 0.2.2-beta supports the game updates of September 1 and 2; it refuses connections between different game builds. Check both the game and the mod on every machine before the host starts a session.

Choose one installation channel. A Steam Workshop subscription installs and updates Going Public through Steam. If you already use BAMP Manager, close the game and use Install / Update instead. The Manager locates the Steam installation, backs up an existing mod installation before replacement and offers Repair for missing mod files.

1. Open the Going Public Workshop item below and subscribe, or update your existing installation with BAMP Manager.
2. Keep only the Workshop copy or the local Manager copy. If the mod reports a duplicate installation, remove the extra copy named in that notice.
3. Let installation finish, then launch Big Ambitions and look for the purple Multiplayer entry in the main menu.

Install Going Public through Steam Workshop

Host a new city or resume a save

The host chooses the world that everyone enters. Use Host New Game for a fresh multiplayer city. Use Host Saved Game to continue a multiplayer save; that option is disabled when there are no loadable multiplayer saves.

Each participant runs their own companies, money, staff and buildings in the shared city. Business access lets an owner invite another player to help with tasks such as stocking and staffing. Joining the same city does not automatically give a guest control of every business.

1. Choose Multiplayer, then Host New Game or Host Saved Game.
2. For a saved game, select the multiplayer world you want to continue.
3. In the lobby, use Invite Friends and let your friends accept the Steam invitation.
4. Once the group has joined and the lobby settings are ready, the host selects Start Game.

Join a friend through Steam or LAN

For Steam play, accept the host’s invitation or right-click the hosting friend in your Steam friends list and choose Join Game. Steam relay handles the connection without requiring you to forward router ports or exchange IP addresses.

Direct IP and LAN remain separate options. Open Multiplayer → Join Game, enter the host address and the port shown by the host, then select Connect. Players on the same network use the host’s LAN address. Internet connections by direct IP require the host’s UDP port to be forwarded; Steam relay avoids that setup.

Continue the same multiplayer save

The host’s save contains the participating players’ characters. To continue, host the saved multiplayer world and have the group rejoin it. Loading an older save restores each player to that save’s moment in time; a character created after that save starts fresh in the older world.

Version 0.2.2 restores multiplayer quicksaving and corrects the timestamp on the save made when a player disconnects. The Manager’s installation backup protects replaced mod files; treat it separately from your campaign saves. A mod-file backup is not a substitute for keeping the multiplayer save you intend to resume.

Fix version mismatches and missing multiplayer

Read the message in the lobby before changing network settings. A game-build mismatch requires everyone to update Big Ambitions. A mod-version mismatch requires the whole group to use the same Going Public release. Matching only one of those versions is not enough.

For a missing Multiplayer button, check the startup notice for an incompatible mod or duplicate installation. BAMP Manager can repair missing local mod files with the game closed. If an invitation window does not open, enable the Steam overlay. For a persistent failure, use Report a Bug from the Multiplayer menu or the purple report button in the in-game top bar.