Stargate is the sequel to Defender, sort of a deluxe version if you will. Just like in Defender, you control a spaceship that shoots and flies, moving up and down and to the left and right, around an alien world. Once again, the landscape of this world is composed of mountains that you can shoot and fly right through. Scattered along the mountain range, there are innocent humanoids. When a lander makes off with one of your men, you can swoop down and save him. Be careful not to shoot the humanoids.

Your primary objective, other than keeping your ship and the humanoids safe, is shooting space scum. Along with the cast from Defender (bombers, mutants, saucers, etc.), you'll face new creatures such as space guppies and Munchies. A scanner at the top of the play field clues you in on what's going on in parts of the world that you cannot currently see. Unlike the scanner in Defender, this one gives you messages as well.

The primary difference between Stargate and Defender is the addition of (surprise) a Stargate. Fly into this little box and you will immediately warp to the area where landers are abducting your men. Also, this game features an Inviso Antimatter Cloaking Device, which temporarily makes you invisible, invulnerable, and deadly to the touch. ~ Brett Alan Weiss, All Game Guide