Revealing mistake: Although Lois and another passenger move violently to show that the train is running wild, the rest of the passengers and the straps to hold one self remain perfectly still.
Other mistake: When the visitors are leaving the museum, the first man from the cue stares at the camera for a brief moment.
Visible crew/equipment: When Nuclear Man enters the building after being told he would be taken to Lacy, he flys upward through different floors. As he's doing this you can see support wires attached.
Continuity mistake: By the colour of the new stones repaired, you can tell that the first gap that Superman fixes at the Great Wall is smaller in size and triangular shaped, instead of the original rectangular and huge gap made by Nuclear Man.
Continuity mistake: When Superman and Lois are flying together, the train below drives from right to left, but half a second later it is moving in the opposite direction.
Continuity mistake: After Lois and Clark read the headline with the "Drop dead" to kid, shots alternate between each of them and there's no sync in the graphics appearing on the computers behind each, while for the rest of the whole film all computers are in sync.
Continuity mistake: After the volcano erupts, a big black cloud covers the city, but a wider angle shows the sky clear.
Continuity mistake: After nuclear Man crumples the cab's hood, there's another taxi behind starting to drive slowly towards the damaged cab. A frame later, a new angle shows that taxi repeating the previous movements but really fast.
Audio problem: When Nuclear Man knocks out Superman on the moon we hear some growling, but their mouths aren't moving.
Continuity mistake: The SWAT van is lifted next to the curb, but a second later appears in the middle of the street surrounded by cars.
Continuity mistake: Luthor extends his arm with a dollar bill in hand for Nuclear Man to light. From the front his arm is fully extended. From behind it isn't.
Continuity mistake: When the SWAT van is turning around, the cars on the street are different than the ones in previous shots (try to find the destroyed taxi cabs that collided).
Continuity mistake: When Nuclear Man is thrown down the chimney, he is unconscious with his arms and head looking down. A frame later he is stiff, with his arms up and pointing to the sky.
Revealing mistake: While flying together, Superman let's go of Lois and she plummets at first, but then, with the snowy mountains behind, she's able to float on air and keep on moving at the same time for 5 seconds.
Continuity mistake: When the crowd follows Superman to the UN the mounted cop changes from being on the left side to the right.
Revealing mistake: While the subway train is gone wild, there's a brief shot of bystanders on the platform. Then the train keeps going on for several seconds, and when it finally comes to a stop the actors are the same ones used previously.
Revealing mistake: When Lenny's car, with the cops in it, flies into the air you can see it's empty.
Continuity mistake: When Nuclear Man walks towards the newspaper on the desk, the phone cable's position changes through shots.
Continuity mistake: Superman crosses flying the Golden Gate Bridge together with Lois, heading close to the bay area. Half a second later they are next to the bridge again.
Continuity mistake: When Superman stops the subway train, there's a black man with a moustache, red shirt and a gabardine suit in the first line. Then he manages to appear meters behind, despite the jam on the platform. Then Lois appears behind him. Then she magically disappears and he appears back on the front.
Answer: Lacy had gotten tired of her dad's newspaper, big-city life and decided to move to Smallville because she wanted to experience life at a much slower pace and even decided to live on a farm.