World War III happens. The crew at a remote U.S. Air Force missile base survive the war, but following an accident which kills several of them and destroys most of their supplies, the remainder decide to make their way across the country to the only part of the U.S. that is still inhabitable. Unfortunately, the only way to get there is a narrow strip of not-quite lethal wasteland, dubbed by the leader of the expedition as "Damnation Alley". As the name suggests, it's no picnic. They set out in a pair of "LandMaster" armored vehicles, encountering various dangers and other survivors as they travel east.
The LandMaster prop is arguably the best thing in this movie, and went on to have almost as long a career in cinema as the human star, Jan-Michael Vincent.
Best known for being the blockbuster 20th Century-Fox was expecting in the summer of '77, if not the one they got.
The movie contains examples of:
- Awesome Personnel Carrier: The LandMaster. Armed to the teeth with rockets, mortars and machine-guns, amphibious, large enough to hold several people comfortably (complete with bathroom and shower), an internal navigation system and radio, with a triple-wheel arrangement on each axle that allows it to go over obstacles with minimum fuss. Doubling the awesome is the fact that the thing actually worked. This interview by Dean Jeffries showcases the awesome.
- After the End: World War III came and went and the world was devastated up to eleven (at one point, it's revealed that Earth's axis has shifted by 90 degrees).
- Alien Sky: The sky is in a permanent aurora borealis due to Earth literally being knocked off its axis by the multiple nuclear detonations.
- Apocalypse How: Class 4. Earth's flora and fauna have either gone extinct or been irrevocably changed by the radiation, and unlike the novel there's no mention of any organized human settlements beyond Albany.
- Attack of the Killer Whatever: The cockroaches of Salt Lake City.
- Base on Wheels / Big Badass Rig: The LandMaster.
- Giant Wall of Watery Doom: The final obstacle before the film's end is a massive flood that wipes out Detroit.
- Black Dude Dies First: Strictly speaking averted, in that he's not the first of the group of survivors to die, but he doesn't come close to surviving the trip either. The fact he is played by Paul Winfield assures his fate.
- Cockroaches Will Rule the Earth: The survival team makes a brief stop in what's left of Salt Lake City. Of course, everyone's dead, and most of the taller buildings were leveled. The first clue that something hungry is afoot is a pair of human skeletons seated in a car, where even the upholstery is gone, leaving only the springs and frames. The team becomes target of a swarm of huge cockroaches, about 10 inches (25 cm) long. The protagonists bug out of there, minus Keegan, who was last seen about to be nibbled to death.
- Cosy Catastrophe: The people of Albany have apparently been doing quite well despite the catastrophe.
- Creepy Cockroach: A swarm of flesh-eating ones, capable of leaving their victims Stripped to the Bone, devours Keegan alive.
- Death World: Earth, after the nuclear exchange. Narrative titles point out that the weather has gone mad, among other things, and the titular "Damnation Alley" is explicitly the path of least resistance through the irradiated wasteland.
- Department of Redundancy Department: During the nuclear war in the prologue, one of the soldiers for some reason feels the need to clarify that the incoming Soviet nuclear missiles headed for major cities are hostile.
- Didn't Think This Through: The soldier at the start who smokes in the gas valve room with a clear sign warning not to smoke ends up blowing the whole base and kickstarting the road trip plot.
- During the War: The prologue follows the main characters as they watch WW 3 unfold.
- Eaten Alive: Keegan gets nibbled to death by cockroaches.
- Last Fertile Region: While the rest of the world is portrayed as a barren wasteland, the area around Albany is rich with grass and trees.
- Reclaimed by Nature: The city of Las Vegas has been reclaimed by the desert (except for a few buildings such as the Circus Circus Casino) in the handful of years following World War III. The climax of the film involves the protagonists being smack in the middle of a freak storm that does this same thing to Detroit — by means of a titanic flood.
- Road Trip Plot: From the Nevada desert to Albany, New York (the only safe zone left in post-nuke America).
- Safe Zone Hope Spot: Blithely subverted with Albany. Although it's discussed early on that it could be this trope played straight (an automated radio broadcast, etc), the town survived.
- Scary Scorpions: Giant mutated ones make a brief appearance.
- Tagalong Kid: Billy. They find him wandering the badlands and take pity on him.
- The Swarm: The cockroaches again.
- There Was a Door: The LandMaster is used to blast into and out of a parking garage.
- Title Drop: The "Damnation Alley" is a pretty vague route from one coast to the other, defined by it being a series of interconnected spots of terrain that have been (comparatively) less irradiated.
- Too Dumb to Live: Keegan takes cover from the flesh-eating cockroaches in a car containing the skeletons of two previous victims that he had seen earlier, because it obviously worked for them!
- Truth in Television: The accident that devastates the military base was a fire started by a guy who nodded off while smoking.
- Wacky Wayside Tribe: A small group of survivors (hinted to be cannibals) threaten the companions at one point. They are disposed of easily, with a few head shots, a well-thrown rock, and the LandMaster's rocket launcher. They are the only human enemies that appear on the whole film.