Revealing mistake: When Superman drops the elevator containing the imprisoned Nuclear Man on the moon, he flies off and lands to straighten the American flag. In this shot you can plainly see the wires helping him land.
Continuity mistake: During the Great Wall of China scene, the sky changes from cloudy and grey in the shots involving people, to bright and sunny when the wall explodes.
Plot hole: Superman dropping Nuclear Man in the area of a nuclear plant would have made him much stronger, since that is giving him a lot of nuclear energy. Instead he is killed.
Continuity mistake: When Lacy is about to enter the elevator, a light brown rug has appeared on the floor behind, which disappears in the next wide shots.
Continuity mistake: In the museum, while the guide is walking towards Superman's hair, people suddenly appear on the left taking pictures.
Continuity mistake: When Superman arrives at the UN, Jimmy Olsen stops in the middle of the street to take a picture of him. A shot later he's six feet behind a dark car.
Revealing mistake: After they fall off the balcony, Superman chases Nuclear Man, but the boats beneath don't move.
Audio problem: When Lenny drives his car into the quarry, the sound of his radio changes depending on where the car is; but when he drives away, suddenly it stays constant. It should have decreased, and increased when we get to the close-up.
Continuity mistake: While Superman flies with Lois, the sky keeps changing colour all the time.
Plot hole: Superman manages to find bricks to rebuild the Great Wall of China. While it's true that he could have created the bricks from stones, the humongous explosions of the wall, and the vast grounds surrounding the area, show that there is no place, no material, and no way even for Superman to create 1,000 bricks from nothing.
Suggested correction: This is the same Superman that flew around the earth fast enough to reverse time, for all we know the bricks came from the other side of the planet, and he just zipped over there in an instant to grab them.
Continuity mistake: When the statue of Liberty is about to crash on the street, a close shot is seen of jammed cars and hysterical people. When the shot changes to Superman flying to the rescue, the jam, the cops and the people have disappeared, and all is nice and quiet in Metropolis.
Continuity mistake: When the volcano erupts, there's suddenly a lot more snow on the crater.
Continuity mistake: When Lois opens the terrace doors in the hotel suite, the angle changes and the furniture on her right moves several meters to the left, appearing close to Lois.
Continuity mistake: In the gym, a man leaves a towel on a low wall. Watch the blue and grey stripes and you'll notice that its position is different between shots.
Continuity mistake: When Superman flies away from the tower holding the elevator, the first angle shows him leaving towards a 10 o'clock direction. A frame later the position of the cable shows him leaving to a 7 o'clock direction.
Continuity mistake: When Nuclear Man and Superman fall off the balcony and fight, the position of their bodies has no continuity in the wide and close shots.
Continuity mistake: In the quarry, the cop on the right's hat has two strings around the top, the upper one dissapears depending on the shot.
Continuity mistake: The UN building that Superman walks towards and the one he arrives at in a new shot look entirely different.
Continuity mistake: When Luthor introduces Nuclear Man to Superman, a towel on a chair changes from ironed and flat to a big bundle in less than a second.
Continuity mistake: When Nuclear Man is about to land on the Great Wall, the aerial view shows it's empty; a second later it's filled with people.
Suggested correction: Dropping nuclear man in to a nuclear power plant isn't as silly as it seems, assuming that the nuclear power is far greater than nuclear man he would simply be absorbed by it rather than growing stronger.
That never got shown and the fact that he was able to make a volcano erupt speaks volumes.
Athletic Jason