Continuity mistake: At the employment office the way papers are arranged on the counter changes from messy to tidy between shots. Also, the blue stamp behind the red one appears and disappears randomly.
Revealing mistake: When the phone booths fall they don't have any cables attached underneath, revealing they're props.
Continuity mistake: Outside the bar, while the people are watching, Superman raises a glass and drinks a shot of whiskey. A frame later, inside the bar, he is already refilling his glass.
Continuity mistake: Superman saves a drowning man in a car on the middle of the street, but when he takes off he's in a children's playground (the DVD extras show the playground scene was deleted).
Other mistake: While on the skiing slope, Gus catches speed and skis away. The problem is he is always on the flat side of the slope, it's impossible to gain speed.
Continuity mistake: In the bowling alley, right before Clark sneezes, the alley on the left has all its bowls standing. Half a second later there are just 5 standing. No sound of them falling was heard in between these two shots.
Continuity mistake: When having a picnic in the wheat field, Clark and Lana's position to the tree and the car nearby changes between shots.
Continuity mistake: After the blind man walks through the painting, the shape of the broken part changes on the angle behind.
Continuity mistake: In the bowling alley, before Clark sneezes, his hands are covered in talcum powder. A second later he raises his hand to fit his glasses and it's clean.
Continuity mistake: Inside the bus to Smallvile, the landscape outside is always an empty and vast wheat field. However, from the shots outside, it swaps to a huge factory. This changes back and forth.
Continuity mistake: The driver's window in the cop car by the burning factory swaps from rolled up to halfway down between shots.
Continuity mistake: Vera stands to turn the TV off in the close shot and a second later, in the aerial shot, she repeats the movement.
Continuity mistake: The file footage of the torch shows it's burned around the rim. When the shot changes to fiction footage the burning is gone and the metal is spotless.
Continuity mistake: When Superman fixes the tower of Pisa, the Italian seller turns his head around. The movement cuts to show a new angle but the new movement is totally different to the previous one.
Continuity mistake: In the end, when Brad jumps on the bed, the wide shot shows him stepping on the right end of the mattress, but the close-up shows him stepping on the left end.
Revealing mistake: When Superman fixes the Pisa tower, there's a wire on the left side, most probably the system to move the prop.
Continuity mistake: While Jimmy Olsen looses balance on the ladder he holds himself but stays on the ladder. A second later he is already off of the ladder about to fall down.
Continuity mistake: When the chemicals explodes, the firemen by the chimney fall down twice.
Continuity mistake: At the chemical plant, while Superman is breaking the chimney, a worker at the far right climbs up twice.
Continuity mistake: At the chemical plant, while Superman is grabbing the chimney, a worker in the back with a blue helmet aids a man to climb up. But in one of the shots in between he's seen away from him, doing something totally different. Then in the next shot he is back helping the guy.
Answer: There were rumors that Hackman was angry with the Salkind Brothers (the producers) for firing director Richard Donner, though Hackman later disputed saying that. His explanation, though he may have been downplaying the real reason, was that he had a number of other movie projects at the time, and he also did not wish to continually play the same villain in an ongoing movie series.
raywest ★