Aliens are attacking and they just want to conquer the Earth.  Their technologies is far advance than ours so the world government can't do anything about them.  However, there is one scientist that isn't ready to give in.  He ask the government to help him create the most advance space craft.  From then on, the spacecraft - Galaxian was born.  The game is based on the old Nintendo game decades ago.  The idea here is to destroy all the aliens before they can pass you.  After you destroy all the the alien crafts will you only be able to go to the next level.