There should be something to enhance the playability of the 'space' stage, as it is very repetitive and doesn't offer any advantage for extending gameplay... it would be nice if there was something more exciting. Here are some ideas I thought of: asteroids of different sizes and positions (which would give different points based on their size), a points increase based on the duration of the game (like a 10% increase every 10 km), and a final boss (!!!) at a certain distance (like at 60 km).