Continuity mistake: Superman stands on a flag pole outside one of the windows in Perry's office to defy the 3 villains. When the shot cuts to an outside view of the villains flying, the flag pole has disappeared, and the nearest one is several feet to the left.
Continuity mistake: When Luthor is at Perry's office door, his hair changes from long and messy to short and combed in the next shot.
Other mistake: When Ursa, Non and Zod first arrive on earth, watch out for the horrible lipstick marks on Ursa's teeth as they walk away from the lake.
Continuity mistake: When Lois is falling on the elevator, the camera angle cuts between her reactions and the ground coming up quickly. When Superman arrives to save her, there is suddenly a LOT more distance from the elevator to the ground than there was just a moment before.
Continuity mistake: Zod punches Superman and makes him fly backwards and crash against a metal structure. The wide shot shows him in the middle of it, but in the immediate close one, he is located on the right side.
Revealing mistake: The fire that comes out of the flame throwers moves at a slow speed though the scene is developing at normal speed.
Continuity mistake: In East Houston, after Ursa says "your general wishes to speak" a sudden change of light takes place and her face swaps from shady to very bright.
Continuity mistake: When the TV camera focuses on Zod, there's a man crouching by a car behind him. Half a second later he is standing and leaning on the hood.
Deliberate mistake: When the villains rampage the White House, the flag's base remains on the ceiling, and the flag pole falls inside the house. So the final scene with Superman carrying the flag and its base as if it had been previously stolen or destroyed, is nonsensical, but it looks very patriotic indeed.
Continuity mistake: In the Niagara falls, when Superman brings Lois a hot dog, the wider angle doesn't show a woman with a beige sweater coming form the right, who suddenly appears in the close up.
Revealing mistake: After Superman saves the kid at Niagara Falls, he lands on a lawn nearby. Then wires holding him are visible.
Continuity mistake: While Superman is crushing Zod's hand, there's a close-up of Non watching the scene in awe. In the following shot, Non's expression has changed to normal.
Continuity mistake: After Zod grabs the cop's rifle, a close-up shows the rifle's butt close to the policeman, which is inconsistent with the next shot where the villains are seen many meters away.
Revealing mistake: When Zod is thrown by Superman and passes by Luthor, the stand in is a guy with fluffy hair who looks nothing like Lex.
Continuity mistake: When Non lifts the cops' car, the fat cop starts to tuck his head inside the car, but a frame later it's already in, without having finished the movement.
Continuity mistake: In the big fight in Metropolis Ursa chokes Superman, but a frame later she is 3 meters away from him and her hands are off his neck.
Plot hole: When Superman becomes human for Lois, the molecule chamber nearly rips him apart, he suffers. At the end of the movie, when he tricks out of the evil 3 and turn them into humans with the same radiation, they are just looking around, wondering about the strange lights, but don't suffer at all.
Suggested correction: Well it's established that Superman has altered the machine. Maybe he also reprogrammed it to not leave signs of their powers being removed.
Continuity mistake: Under the elevator when Lois says "Nobel prize" her fingers are completely black, covered in grease. When she starts to say "lil' o" they're just slightly dirty. When Superman saves her they're spotless.
Continuity mistake: Non attacks the guard, who activates an alarm on his belt. In the wide angle all of his left hand is on the alarm, on the close-up only the index finger. This keeps swapping back and forth.
Revealing mistake: After the Marlboro truck scene, Superman throws Zod and he goes through an office window. The harness to make him fly is visible on his back.
