You must learn to control the laser beam to destroy the aliens before they
conquer the Earth. Press the red button on your Joystick to begin.
The alien ships attack from the upper part of the screen in groups of eight.
The laser is located at the bottom of the screen. To emit a laser beam, press
the Joystick button.
When the alien ships first appear on the screen, they will be in strict
formation, moving from right to left. Don't trust them for one minute
because they're sneaky!