Hello GanguEevee, the entire game doesn't have to take place in space.
Space can just be something beyond earth. The game could take place in a rocket ship or on a planet way different from earth.
Or maybe it takes place on earth though a meteor is going to crash onto earth destroying the planet, so they send up a bunny to save the day.
The game just has to have something space like but it doesn't have to be in outer space. I hope that makes sense.
Thank you for asking this question and I hope you have a wonderful day.