Stargate

This is Williams sequel to Defender. This new version adds new ships to the alien fleet, including Firebombers, Yllabian Space Guppies, Dynamos, Phreds, Big Reds, Munchies and Space Hums.

The Defender ship is now equipped with an Inviso cloaking device, which renders the ship invulnerable when activated, but has a limited charge. A Stargate transports the ship to any humanoid in trouble.

There are two special stages: the Yllabian Dogfight, first appearing at wave 5 and recurring every 10 waves; and the Firebomber Showdown, first appearing at wave 10 and also recurring every 10 waves.