Once you've done this, simply load RimWorld, click on the mods tab in the menu, and enable the multiplayer mod (don't touch 'core' or things will start breaking). You'll need to unpack Multiplayer.zip (once unzipped) to RimWorld's 'mods' folder, which you can find through Steam by going to a game's properties then location files.

After a slightly bumpy start in which someone downloaded the wrong file ( make sure you choose the latest version, currently 0.4.4 Multiplayer.zip), we soon figured out how to get the mod up and running. To test out the mod, I enlisted the services of Eurogamer's seemingly-only-other RimWorld fan, Matt Wales. Technically you can add up to 999 players, but the recommended max is eight. It's an incredibly smooth and professional experience, although as the mod isn't in the Steam Workshop, so you'll need to do the installation process yourself (it's quite simple). In terms of features, the mod boasts hot joining, hosting from existing saves, chat, and the ability to connect with Steam friends.

Rimworld man in black