To stay alive, you must blow up the huge floating asteroids before they hit your spaceship. When you shoot a large asteroid, it breaks into two medium-sized asteroids. When you shoot a medium-sized asteroid, it breaks into two small asteroids. Fortunately, when you shoot a small asteroid, it disintegrates. Keep an eye open for large flying saucers and small flying saucers.
Asteroids is easy to play.
All you need to know is how to start a game, fire missiles, and move your spaceship. Beyond that, you're on your own for hours of daring expeditions through space.