Defender

Defender is a clone of the Williams arcade classic Defender.

You are out in your ship equipped with deadly lasers and a limited number of smart bombs flying over a planetary landscape on a mission to protect the humans that are under attack by the aliens. The player patrols the two-way scrolling landscape in his ship, preventing the marauding aliens from abducting the humans. If the aliens manage to get a human to the top of the screen, it mutates into a super alien hybrid that will come after you, resulting in a fatal collision if not dealt with. Each surviving human gives you a bonus at the end of each stage.

The top portion of the screen is dedicated to a scanner, or radar that shows the location of all enemies and humans on the level. You start out with three lives. Each time you get hit by an enemy projectile you lose a live, once all lives are spent the game is over.

It was later rereleased under the name Planetoid due to legal reasons.