The Robotrons have risen against their creators, and are now bent on exterminating all humans! As a genetically modified being with superhuman powers, you are mankind's only hope for survival. Blast wave after wave of oncoming Robotrons while saving the last humans on earth!
Several different types of Robotrons will work to stop you, while some will also kill any humans they find. The first type you will face is the Ground Roving Unit Network Terminator, or GRUNT. GRUNTs lumber slowly toward you, relying only on their numbers to overwhelm you. GRUNTs are easily picked off, but can surround you in a hurry if you're not careful.
Hulks are indestructable mechanical beasts. They don't chase you, but they will still destroy you if you touch them. Hulks' main mission is to seek out and kill any humans caught in the mayhem.
Spheroids zip back and forth across the playfield, at least when they're not hiding out in the corners. Left alone long enough, a Spheroid will begin producing Enforcers, small, quick robots that fire at you as they come for you. A pack of Enforcers can easily outgun you, so kill the Spheroids as quickly as you can!
Brains are the most sinister Robotrons of all. They fight with two weapons: homing missiles and humans! Brains will reprogram any humans they can catch, turning them into merciless Progs.
Quarks are among the last unique types of Robotrons you will encounter. Like Spheroids, Quarks move across the playfield until they are ready to create more robots. These new robots, Tanks, are every bit of a pain as Enforcers, only Tank bullets can bounce off the walls and hit you from behind!
As if dealing with the Robotrons wasn't enough, the playfield is littered with Electrodes, stationary objects that don't fire, but are still quite deadly! Electrodes are lethal to anything that touches them, meaning you can use them in your strategy against the Robotrons, as long as you don't run into them yourself!
The humans you are responsible for rescuing wander aimlessly around the playfield, apparently shellshocked by the Robotrons' betrayal. Rescuing them means touching them before the Robotrons get to them. Most Robotrons actually will leave the humans alone, but Hulks and Brains in particular work actively to wipe them out, or worse! Rescuing humans is not necessary to complete a level, but they are worth a lot of points. Just be careful you don't become so intent on rescue that the Robotrons kill you without even trying!
Once all the Robotrons (except Hulks) have been destroyed in a level, you are off to the next level, where another mass of robots awaits, and another group of humans hope for rescue!