GoldbergLocalCoop
Enables local co-op multiplayer using Goldberg Steam emulator. Play with friends on the same machine!
About this mod Author’s original text
Goldberg Local Coop
Enables local co-op multiplayer for Risk of Rain 2 using the Goldberg Steam emulator.
What This Does
This mod patches RoR2's networking layer to properly handle P2P connections from Goldberg Steam emulator instances. Without this mod, joining players get disconnected when the host starts the game.
Use Cases
- Local co-op: Run multiple game instances on the same machine
- LAN parties: Play without Steam authentication requirements
- Offline play: No internet connection needed
Requirements
- BepInEx (mod loader)
- Goldberg Steam Emulator (Steam API emulation)
Installation
- Install BepInEx if you haven't already
- Download this mod
- Place RoR2LocalCoop.dll in BepInEx/plugins/
Setup Guide
For Each Game Instance
- Create a separate game folder with Goldberg's steam_api64.dll
- Configure unique Steam IDs in steam_settings/ for each instance
- Launch both instances
In-Game
- Both instances: Settings -> Disable crossplay
- Host: Multiplayer -> Host Game -> Create
- Host: Copy Lobby ID to clipboard (button in lobby)
- Client: Multiplayer -> Join Clipboard Lobby
- Host: Click Start Game
- Both players load in!
How It Works
When RoR2 receives P2P network data, it checks if the sender has a registered connection. Goldberg emulator connections weren't being registered properly, causing data to be rejected.
This mod:
- Force-accepts P2P connections from Goldberg Steam IDs
- Properly registers the connection object so data isn't rejected
Goldberg Steam IDs
The mod automatically allows Goldberg's default ID range:
- 76561198000000001 through 76561198000000010
Compatibility
- Works with most other mods
- Does not affect normal online multiplayer
- Only activates for Goldberg Steam ID ranges
Source Code
GitHub Repository
Credits
Built with BepInEx and Harmony.
Install & use Install: BepInEx plugin
- The archive from playbuff is the mod itself — usually a BepInEx plugin (a .dll or a plugin folder once unzipped).
- Recommended: use a community mod manager (such as r2modman) — pick this game, import the mod, and the manager sets up BepInEx and its dependencies for you.
- Manual route: install the BepInEx loader in the game folder, then drop the unzipped .dll or plugin folder into BepInEx/plugins/.
- Launch the game — the BepInEx console logs every plugin it loads; seeing this mod in the log means it is installed.
Mods with listed dependencies need those installed too, or they will not load. Options are usually changed in-game or in the plugin's config file.
Install these first, or the mod will not work: