Running a submarine as a crew
Barotrauma is a 2D survival horror sim set under the ice of Jupiter's moon Europa, where humanity now lives. You and your group occupy one submarine and everything aboard is a real system to operate: sonar, nuclear reactor, engines, pumps, weapons. Steering, power, ballast and damage control all need hands, so a crew splits into jobs and talks constantly. Missions are procedurally generated and you pick contracts from four factions — help one, gain their trust and rewards, or earn their hostility. The world is procedurally generated too, so routes and objectives differ between runs.
Filling the bunks
A submarine takes up to 16 players, and bots can pad out the crew in both singleplayer and multiplayer modes. Six classes define what you're good at: Captain, Engineer, Mechanic, Medic, Security officer and Assistant. Each class has three specialization talent trees, and you gain experience and talents as you play, so characters grow into the role you keep giving them. Engineers keep the reactor and wiring alive, mechanics handle hull and leaks, medics deal with wounds and the medical system, security fights what comes out of the dark. Communication is the actual mechanic here — sonar contacts, reactor load and flood warnings mean nothing if nobody says them out loud.
Sabotage and betrayal
Cooperation is optional. Traitor modes put someone on board working against the crew, and the game supports PvP on top of co-op, so your worst enemy can share your hull. Ragdoll physics, flooding and fire make a single mistake cascade: a hole in the wrong compartment takes the whole boat down.
Building, modding and systems to learn
There's a full crafting system for equipment, weapons and medicines, plus complex on-board wiring to master. Built-in editors let you make your own submarines, characters and procedural animations, and mods are shared through Steam Workshop. Most game data sits in .xml files and the source code is public, so the modding side goes deep. Expect a learning curve before your crew stops sinking: read the systems, agree on roles, and start simple.