There is no air in space and almost zero gravity. When the astronauts goes into the open space outside the ship, he can fly far away in an unknown direction, slightly pushing away from any object. Therefore, walking in outer space is better on a leash. But our hero in the game Gravity Control will be free, because he will be in a labyrinth of caves. He went there to collect rare crystals that need to be delivered to Earth. To move, you need to build on the walls. These labyrinths are clearly built by someone, they have a security system, which is unknown to earthlings.