A mothership drops aliens, up to three on screen at a time. There are ten per level. You must shoot them but avoid the items they fire at you. You fire by pushing up on the joystick. Pushing left or right makes you go left or right. If you hold down the button, pushing left or right makes you fire left or right. Later enemies will drop fireballs that chase you along the ground or split in two smaller enemies when shot. If you fire non-stop, you will build up heat as indicated by the green bar at the bottom right. If you overheat or are hit by an enemy, you loser a life. The game is over when you lose all lives or reach a score of 999,999. You get a new man (4 max) every 10,000 points.
Pilot Star Voyager through treacherous space. As you look out from the Command Bridge, stars rush past. Penetrate the seven star portals and save the Capital Starport. Destroy enemy ships with photon torpedoes or lasers, or evade them to maintain your precious energy supply.
Keep track of energy levels on the instrument panel. Use your radar screen to locate opponents and approaching star portals. Only passing through a star portal restores your energy reserves. But be warned! Crashing into a star portal will destroy you!
The object of Alpha Beam is to help Sesame Street's Ernie pilot a small shuttle, collect fuel tanks (marked by a letter of the alphabet), and return them to his space ship so that he can return to Earth.
The game was marketed as a family-friendly game that could teach children pre-reading skills such as identifying and matching letters. Alpha Beam was compatible with the Atari Kid's Controller, which was sold separately, although the regular keyboard controller is also compatible