Space Station 13 (and its successor, Space Station 14) is a multiplayer roleplay / job simulation / disaster survival game. It's a little hard to describe! Everything takes place as a round that generally lasts 1-3 hours, though you can join or exit the round at any time in the shift. Almost all servers have some level of roleplay to it, with some servers being on the lower end (more wacky gameplay hijinks) and some being on the higher end (establishing characters and relationships and arcs across many rounds).
The gist is that you are one crew member on board a space station, alongside all the other players in the game, spread across multiple departments. For the most part, your only goals are to do your job and keep the station running. You might be an engineer, a doctor, a chef, a security officer, a scientist... there's a lot of roles you can take up. However, due to ramping events and enemy activity, inevitably the station will become uninhabitable, prompting an evacuation (which ends the round).
SS13 is quite well-known for its mechanical complexity and dynamic systems, but each player is only going to interact with a small slice of these mechanics. For example, say you are an engineer, so your job is to set up an engine to generate power, and fix structural damage to the station when it arises.
- You might need to talk to the Cargo department to acquire materials or extra power generators (like solar panels).
- The Science department can research upgraded tools that you can ask for, or they might call Engineering over the radio to provide them with atmospheric gases.
- Maybe you get attacked while repairing cable networks, and you have to get wheeled over to the Medical department for revival.
It's also open-source, and each server of the game is a self-contained copy of the game's entire code. This means, between different servers, you might play the same game with different mechanics and content. In fact, some people have done crazy total conversion work for SS13/14, turning the game from a space station survival simulator to, among other things: a "marines vs. xenomorphs" team PVP gamemode, a dark fantasy kingdom roleplaying game, an MMO-esque space exploration game where everyone's split into dozens of small crews on little spaceships, and a recreation of Lobotomy Corporation using SS13 mechanics.
Space Station 13 is hosted on the BYOND game engine, and the SS13 server browser is found in the BYOND launcher. It's been going strong since 2003. BYOND is notable for how fucking old and kinda shitty it is (the launcher is NOT malware despite how it looks), but SS13 is also quite iconic and mechanically rich. Mind the learning curve, however.