Planet Raider

Planet Raider is based on the arcade smash hit, Defender, but has some differences. You are flying over a planet, trying to rescue humans, but the humans don't get picked up by aliens (you have to pick them up off of the ground, like in Broderbunds Choplifter for other platforms). All aliens are stationary on the terrain (except for one type of ship that will launch and try to kill you), but some of them are firing at you. You can also shoot the humans by accident, and fly in all directions (like Defender).

The terrain (and the objects on them) are in a fixed pattern... if you clear out half of the mountain range, and die, when you get your next life everything will be empty until you fly back to the point you were killed at. A bigger difference is that after you have rescued all humans (and it is not necessary to destroy all the aliens), you have fly off the top of the screen to complete the wave. If you have destroyed all aliens and rescued all humans, but do not fly off the top, you will fly around forever on an empty planet.

The skill level makes a huge difference in the game. The Easy level has fewer shots from the enemies, and the aliens that do launch at you are not very aggressive. The Hard level lets the aliens have more shots, and the launching aliens are much more aggressive. Impossible is close to what it says; unlike the two easier levels (where you fly through the mountains), on this skill level, if you touch a mountain at all, you instantly die. You select the skill level by moving the joystick up and down, and then hitting the 'R' key to restart the game.