A ship of crewmates, one impostor hiding among them. Do your tasks, watch your back, and vote out anyone acting strange. Everything runs on this device against computer crewmates - no account, no waiting for a lobby.
Discuss, then vote.
If you are a crewmate: find and finish your tasks, or find the impostor and vote them out. If you are the impostor: kill crewmates when nobody is watching and use vents to move fast, without getting caught.
There is no map showing where everyone is - the room name in the top-left corner is the only clue to where you are, same as finding your way around in person.