Barotrauma

Barotrauma is a two-dimensional survival action game where you're offered to take control of a submarine to explore vast and yet unknown depths of the ocean at Europa — one of Jupiter's moons. This is a full-blown submarine simulator with a plot twist. Since the game takes place on a moon in outer space, you have to deal with a hostile environment and creatures. Add to this a constant maintenance of the ship that could take a toll on the mental and physical well-being of the entire crew and you'll get intense and exciting gameplay. Depths also are rich in undiscovered minerals that wait for you to extract them. The game is also available for playing with a bunch of your friends in a co-op mode where the results really depend on teamwork and coordination.