- Use the A key to move to the left and the D key to move to the right.
- Press the space bar to shoot your laser.
- Rocks (squares) and gems (circles) will fall from the top of the screen at random intervals. Your goal is to score as many points as possible.
- Points are scored in three ways:
- Shooting down a rock
- Shooting down a gem
- Colliding your ship with a gem.
- You lose points if you collide with a rock.
- The game ends when you close the window it is contained in.