Ostranauts is a simulator of activities in space and control of a spaceship. Players will control a team of astronauts aboard a starship lost somewhere in a distant solar system. The characters here are diverse: each has insecurities, emotions and, probably, some kind of defect. It's a post-apocalyptic world, and the squad finds themselves thousands of miles away from an already destroyed Earth. Each team member has different needs, from basic necessities such as food, warmth and oxygen to the need for intimacy and a sense of security.

The Outlanders has a social combat system – certain characters have social abilities that can make or break your mood. The ship also requires careful control with many interdependent systems that interact with each other – this includes fuel, electrical networks, supplies and much more. Gameplay focuses on a pace that suits the player – you can pause and fast forward to your liking, just like other management sims.

Every component and object on the ship can be interacted with in an immersive simulation, and there are quite a few inventory management tools. Almost all major functions (reactor, navigation, life support, etc.) can only be used in an intermediate way, when the gamer clicks on the astronaut and gains access to control elements.

Once the captain has a crew, his members will join him to operate numerous devices and take up residence on board the starship. They will also interact based on a detailed personality modeling system. The gameplay plays on a mixture of direct control and autonomous action, focusing more on the former. In other words, gamers can “own” crew members to force them to do things directly, but if they don't, they will act on their own.