Goofs

The rifles carried by Ben and Ralph change. Ben is initially shown shooting at Ralph with a bolt action rifle. Later, he is armed with a Remington pump action. Ralph grabs a tube fed Winchester lever action from the sporting goods store, but when he throws his rifle down, it has changed into a Winchester 1895 with a box magazine.

When Ralph throws the mannequin off his balcony, the overhead shots show the sidewalk and street are dry, but all of the ground level shots show everything wet.

When Ralph exits the mine, his previously soaking-wet clothing is completely dry.

The books on the shelf behind the bed Ben is in change order between shots.

Ralph throws the mannequin from his apartment, and its leg is at least three feet from the curb. When he gets down to the street, the mannequin's foot is on the curb.

Someone says over the radio that the radioactive poison was an isotope of sodium with a half-life of 53 hours. There is no isotope of sodium with that half-life.

Near the end of the movie Inger Stevens can be seen running across the street. In the background steam is coming up from the manhole covers which is produced by steam generators providing heat to buildings in Manhattan.

There are no bodies, With 8 million people in NYC, there is not one dead body seen anywhere.

In his kitchen, Ralph shows Sarah how he's been throwing his dirty dishes out his apartment window because there's no water to wash them with. Sarah simply turns on the faucet and water flows, thanks to the water tower on top of Ralph's building. Ralph should not have been surprised by this, as he should have noticed that his toilet was still working. In addition, both they and their hair look spotlessly clean, with Sarah's hair being particularly shiny.

While Ralph is being pursued by Ben near the end, he comes to the United Nations complex. Although there is no electric power in the city, except where Ralph has installed a generator, lights can be seen through the windows of the Secretariat building.

After Ralph telephones Sarah, he tells her to turn on her radio. When she does, Ralph's voice is heard coming through. This occurs without him telling her the frequency he is transmitting on or her adjusting the radio's tuner.

When Ralph is digging himself out of the tunnel, he often knocks himself against rocks. In the instances where he applies little force (such as knocking them incidentally with his elbow), the rocks move easily, showing that the rocks are not real.

When the characters run through the street, the sound of their footsteps does not synchronize exactly with their footfalls; they are a bit off. It's a subtle effect but noticeable.

While Ralph walks around singing and playing the guitar, the whistle on the electric train is sounding without Ralph activating the whistle button on the transformer.

Not only does Ralph wait for five days before (easily) escaping, his ability to do so, including climbing the shaft ladder, is little impaired by his lack of food and clean water.

The recording Ralph listens to states the radioactive sodium half-life is just over two days and that it is deadly for about five days. If they were aware of this, many people would have taken refuge in bomb shelters, basements, caves, etc. and survived. Many families in the cold war era had plans for surviving nuclear fallout, and five days is not an excessive time.

The final scene has a flock of pigeons who miraculously survived the nuclear war.