Sam is hanging out in Central Park, waiting for his girlfriend Sally to show up. Alas, there she is! Sam gets so worked up at the sight of her, he rushes to greet her, heedless of the gaping maw of the manhole in his pathway. Next thing he knows, he is plummeting into the bowels of the city sewer!
Like any good citizen of New York, Sam packs heat -- a revolver to be specific. It's a good thing, too, because the sewers are festering with nasties such as bats, gulls, spiders, sewer grunts, snakes, crocodiles and sharks. If a gull comes in contact with our hero, it will send him back through the sewer, eliminating some of his progress. One touch from any of the rest of the creatures will drop Sam to the floor. One pop from Sam's trusty firearm will put a creature out of its misery.
The gun has six bullets. After Sam fires a full round, a few seconds must elapse before the gun will reload itself. There are three types of sewers: some with solid floors, some with water canals and some with deadly pits. Sam maneuvers from sewer to sewer by exiting through the black passages that line the sewer walls. Entrance into a new sewer will grant Sam with a fresh supply of oxygen; each time he leaves a sewer, the passage is somehow instantaneously sealed off by the City Works Dept.
Sam can walk straight ahead, back the way he came and right and left. He can even swim, climb walls, and talk! When the nasties are coming, he lets loose with "Oh No!" If a nasty gets him, he yells "Ouch!"
So, the question remains: How can Sam escape the narrow underground (not to mention smelly) passages and hook back up with his gal pal? The answer is simple. All he has to do is down three Russian submarines that are prowling the city sewers. You'll find one sub at the end of three of the water canal sewers. When confronting a submarine, Sam must avoid being shot by the sub while trying to shoot down three of its missiles.
Make the sewers of New York City safe once again and help Sam reunite with his beloved Sally. Just be careful and watch your step.