Factual error: Superman places the nuclear missiles in the giant disposable bag in space, throws them at the sun, and the bag burns up when it hits the sun. In reality, the bag would have burned up long before hitting the sun. (00:35:35)
Revealing mistake: Obvious doll replaces Nuclear Man when he falls into the chimney.
Continuity mistake: Lex is a bald man, except for this movie where he has very obviously natural hair.
Visible crew/equipment: When Superman saves the cosmonaut, stage lights are reflected on his visor.
Revealing mistake: When Nuclear Man flies through the ceiling for the first time, the first glass he crashes into is noticeably different than the others surrounding it, revealing it's a prop.
Other mistake: When Lenny has the prison guards locked in the car and is putting the top up, the steering wheel is spinning but the front wheels aren't moving. The amount of revolutions of the steering wheel is mechanically impossible also.
Continuity mistake: After Superman ducks the moon rock, there's a close-up of Nuclear Man's black boot stepping on Superman's boot, yet in the next angle, it's Nuclear Man who's yelling in pain. It should be Superman instead.
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.