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.
Revealing mistake: There are two times in the New York battle when you can see the actors are being filmed in front of a screen: 1. when Superman kicks Non, Superman in on film and Non is hovering in front of the screen. 2. When Ursa is flying towards Non and Superman with the flagpole, she is hovering in front of the screen.
Visible crew/equipment: Ursa throws the sewer lid at Superman sending him flying backwards into the car windshield. Watch the sewer lid carefully when Superman actually hits the windshield. You can see that the sewer lid was actually attached to a belt around his waist so that it would stay in place for the shots where he is flying backward through the air. (01:39:50)
Visible crew/equipment: In the shot where Zod walks on the lake's water, there is a platform visible just under the water's surface.
Visible crew/equipment: When Superman is fighting Non under the New York Streets (in the sewers), manhole covers start to jet up in the sky. When the first manhole cover shoots up you can quite clearly see the gas tube in the hole and the gas cylinder attached to the cover.
Revealing mistake: In the final scene, Superman is returning the White House's flag to its rightful place, flying over the fountain on the lawn...which is frozen solid in place. Obviously a photo backdrop.
Revealing mistake: When Zod lifts the boy's father with the beam of white energy, watch closely when he raises him up past the telephone pole...he 'clips' right through it, or rather the pole clips through him, as if he is transparent.
Revealing mistake: There are two external White House shots in the film. The second is a still shot, and should take place at least a few days after the first. However, it is a frame from the earlier shot, with the same person standing in the same spot on the lawn.
Revealing mistake: Near the end of the film when the 3 villains fly and later enter the fortress, you can see that it was a stuntman and not Gene Hackman.
Factual error: After Superman accidentally frees the phantom zone villains with the exploding hydrogen bomb, they start flying towards the moon. The sleeves in their clothes can be seen fluttering around. This would be impossible because there is no air in outer space, hence nothing to cause resistance against the clothes.
Revealing mistake: In the New York battle scene, after Ursa distracts Superman, Non punches him and he goes flying backward into a building. Watch very carefully along the bottom of the screen. You can tell that Superman isn't even matted in from the chest down. Where is the rest of him?
Revealing mistake: When Non tries to fly at the end of the film, but falls into the bottom of the Fortress of Solitude, watch closely. He appears to hit some sort of safety pad after he falls, making the fog around him disperse very briefly, which shows him safely land on the pad. The fog quickly comes back and covers him as he ducks his head down.
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 they are in east Houston, Idaho, the helicopter gets knocked out of the air and lands upside down onto a jeep. You see the pilot get smashed into the seat of the jeep real hard and yet seconds later he walks away unharmed.
Audio problem: Before the trio crashed into the Daily Planet (just before the battle with Supes), they were heard flying outside the building. For 3 superbeings with the ability to fly unaided, they sure sound heckuva lot like jet-propelled aircrafts. Jet aircrafts are noisy because of their engines, but superpeople?
Revealing mistake: When Zod says to Ursa to "blow them a kiss my dear" to the helicopter that's firing on them watch as the helicopter is indeed a real military helicopter, then when it loses control it's an obvious model and just before it crashes into the house it's a full size helicopter again but is completely different from the first one that was originally shown.
Other mistake: At the end of the film Superman puts the US flag back onto the Whitehouse. Whilst he is speaking to the President through the hole in the roof the flag can clearly be seen flying in the wind, but his cape is completely still.
Other mistake: When Clark and Lois are on their way to the diner, the wide shot of their car driving along looked very familiar. In fact, it was footage used in the first movie, where the car was used as part of Lex Luthor's "real-estate" plan and was run on remote control. If you look closely in part II, no one is driving the car yet you hear Clark say to Lois, "Hey, you seem pretty quiet over there...."
Revealing mistake: In the beginning, when Superman is flying to the Eiffel Tower, the last scene that shows him flying towards the tower, you can see the wire Christopher Reeve was attached to as he swoops down. The wire stretches all the way across as Superman glides down.
Continuity mistake: There must be a barber's shop or a cosmetics shop somewhere in the Phantom Zone. At the beginning of the first Superman film General Zod's hair looks as if it has been blow-dried, but all through Superman II he looks like he uses wet-look gel.
