Hosting and joining
Before you start
Back up your saves. They live in:
%USERPROFILE%\AppData\LocalLow\Massive Monster\Cult Of The Lamb\saves
Only the host's save is modified during a session, but this is a test build and a backup costs nothing.
Host a session
Load the save you want to play, open the pause menu with Esc, and choose
Host Multiplayer. The lobby is created immediately and the pause menu gains
the online controls.
Invite your friend
Invite from the Steam overlay, from your Steam friends list, or through Discord if Discord Rich Presence is on. The guest accepts the invite or joins from your friends list.
Wait for the handshake
On connect the mod compares the protocol version, the MP build, the game version and every installed plugin by file hash. A mismatch stops the join with a message naming what differs, rather than desyncing later.
Play
The guest drops into your world with their own camera and HUD. Press Enter to
chat, middle-click to ping a spot for both players.
In-session controls
| Input | What it does |
|---|---|
Enter | Opens text chat. Steam avatars and lobby events are shown; it hides itself when quiet. |
| Middle mouse | Drops a world ping visible to both players and announced in chat. |
Esc | Pause menu, including the online section and a Pause Game button that freezes both players. |
Rewards, inventory and building
- Dungeon rewards are instanced. Weapons, curses, relics and tarot cards can each be taken by both players. Tarot lists are shared back to the host so defensive cards protect the guest too.
- The cult's inventory is the host's. It is streamed to the guest, and buildings the guest places are paid from it. If the host cannot afford a placement it is refused and the guest's copy is taken back.
- Structures replicate as results. Placement, hammering progress and removal cross over, and you see the other player's placement ghost while they aim.
Discord Rich Presence
While Discord is running you get Invite to Play and Ask to Join, and your
presence shows where you are: the base with a follower count, a dungeon, or a
hub — including CultTweaker's custom hubs and maps. Turn it off in the
[Discord] section of the mod's config file.
Reporting a bug
Send a DM with:
- Steps to reproduce, and whether you were the host or the guest.
BepInEx/LogOutput.logfrom both machines.- If the game crashed,
Player.logfrom%USERPROFILE%\AppData\LocalLow\Massive Monster\Cult Of The Lamb\and the newest folder in%LOCALAPPDATA%\Temp\Massive Monster\Cult Of The Lamb\Crashes. - Screenshots or video, if you have them.
Known limits
- Steam overlay invites do not work on app id 480. Invite through the Discord or Steam friends list instead, and make sure both players use the same app id.
- Not every interaction is patched yet. Anything that shows up on one screen and not the other is worth reporting.
- CultTweaker support varies by build; older versions such as 1.1.2 may not behave.