Shoot the enemy ships to get points.  You control your ship with the arrow keys and shoot with the space bar.  Try to collect the yellow orbs before they fall off the screen.  For every yellow orb you collect, the frequency of enemy ships appearing goes down.  Conversely, for every orb you miss or shoot, the frequency of the appearance of enemy ships goes up.  Finally, when the green "triangulation" enemy ships appear, watch out!  If you are caught in the imaginary triangle formed by three "triangulation" ships, your demise is swift and certain.  Finally, take advantage of the fact that you can gently bounce off the sides of the screen.  Good Luck!!!