Androne

Androne is a Radio Shack cartridge game that involves you travelling a 3D maze battling monsters. Unlike most such games of the time, when a monster showed up, it could float up/down/left/right on the screen, so you had to aim your weapons sights in order to kill it. Also, there are squares on the floor of the maze (ala Pacman) that disappear after you walk over them. There are also elevators between levels, and ways to recharge your shields. Your basic mission is to seek out the generator, and then exit to the next level.