Revealing mistake: In Grand Central Station, the same extras appear in every scene, no matter where in time or place occurs.
Continuity mistake: When Clark is shot by the mugger, his hat falls down. In the next shot, while Lois is screaming, you can see him taking his hat off.
Revealing mistake: After Superman saves the cat, he takes off and wires holding him are visible.
Continuity mistake: When the council tells Jor-El not to worry them, a bald man standing in the back changes positions between shots.
Continuity mistake: The position of the baby when his mother holds him by the cradle differs in the wide and close shots.
Continuity mistake: After Clark runs by the train, a girl in a moving car stands up. In the next angle, a split second later, she is sitting down.
Deliberate mistake: There's no way Lois Lane, a beat reporter for the Daily Planet, could afford living in a penthouse apartment.
Suggested correction: There are plenty of ways for her to afford it. For instance, maybe it belongs to a wealthy relative who lets her stay there when they are out of town. Since any explanation would be irrelevant to the plot, there is no reason for the movie to waste time on it.
Other mistake: Clark does not have enough room beneath his clothes to have the suit, the cape and the boots.
Revealing mistake: Before the Hoover Dam breaks, the places where all the cracks and water will later appear are easily traced on the concrete, covered in plaster and painted. Either that, or the real Hoover Dam has burst many many times and always through the same spots.
Other mistake: Something that happens a lot in films. When Lex Luthor is watching the cops trail Otis the image on Lex's CCTV screen is actually just the scene from the film being played back. The shots change to angles where Lex couldn't possibly have a camera, for instance a close up on the cop holding his partner's hat. This mistake is especially more noticeable in the extended edition where Superman walks through Lex's 'gauntlet'.
Continuity mistake: Near the end of the movie when Superman pulls Lois Lane out of the car and she's already dead, she is very dirty all over because of all the dirt that "drowned" her. In the following shot when Superman is done crying over her and leaves her on the ground to reverse time so that she will come to life again, her clothes are all white and shiny.
Continuity mistake: When the lady of Lex Luthor is in a red dress pretending to be unconscious on the road we see her legs flat on the ground, then in the next shot one leg is standing up.
