At first you will earn points for each thermo-molecular detonator destroyed. As the game progresses, the shower of detonators rains upon Guardian at a more frenzied speed. and you gain more points for destroying them.
Every time you earn 10.000 points, your force field will be re-built.
Every 50.000 points, you gain an additional planet. However, due to the visibility range of Guardian. You can only view three planets at a time. Rest assured that the others are there. The game is over when your last planet is destroyed.