Continuity mistake: The huge lamp post next to the bus on the Golden gate disappears when the bus is about to fall down.
Continuity mistake: At the end of the falling Hollywood sign, the girls are zooming away from the sign. Angle cuts brusquely and, though the sign keeps falling on top of them, the girls are now walking calmly forming a neat cue.
Continuity mistake: When the gas station collapses, at first the roof falls down completely and covers the gas tanks, but in the next shot it's slightly laying sideways.
Continuity mistake: When Hoover Dam is about to explode, there's a shot of a resort nearby. The people running close to the fallen umbrella differ between shots.
Continuity mistake: Superman lands on the sidewalk looking for Luthor and a group of people gather closely together behind him. In the next shot, half a second later, they are standing way apart from each other.
Continuity mistake: When Superman pulls Lois' car out of the quake hole, the camera then does some wide shots, rotating around the scene before Superman flies off. The damage to the front of the car changes in these shots.
Revealing mistake: When Lois falls from the helicopter, the cable holding her is visible.
Continuity mistake: After the van crashes against the beetle car, the new angle shows the van in a different position.
Other mistake: When Superman helps the airplane his "S" is flipped.
Continuity mistake: After Superman saves the train from derailing, there's a wide shot of the lead locomotive and it has just one small window on the side. In the immediate close-up there's a big window where the conductor peeps, and a sudden second window with a handle bar where another engineer shows up.
Character mistake: In the Air Force One scene, when lightning destroys one of the plane's engines, one of the pilots tells a co-pilot to inform Metropolis Airport that the president is on board the plane. The crew is unnecessarily repeating themselves: just a few moments before, they radioed in that "Air Force One" was on approach; the plane would only have that call sign if the president was on board.
Continuity mistake: When the cab arrives in front of the Daily Planet, the sidewalk in front of the office is empty. A split second later there are people everywhere.
Continuity mistake: When Lois interviews Clark, the position of the glasses changes between shots.
Continuity mistake: When the cradle takes off, thousands of glasses fall on the floor, but the next travelling shot shows just four or five around the parents, and the rest of the floor clean.
Continuity mistake: When Superman arrives at the dam, after chunks of concrete have exploded everywhere seconds before, there is barely nothing broken, except for some cracks on the wall.
Continuity mistake: The cheerleading equipment is knocked down from the bench, but magically appears up on the next shot.
Continuity mistake: The Hoover Dam breaks in many pieces with huge cracks everywhere. When Jimmy is hanging about to fall, from his POV there are just four tiny cracks.
Continuity mistake: The first day in the Daily planet, Lois starts typing and a man is sitting beside her. In the following angle the guy is standing several meters in front of her.
Continuity mistake: At the beginning when Jor-El and the council pass judgement on the three criminals and the huge white dome starts to open, it stops about a third of the way. Long shot of the three criminals, it's completely open. Next shot it's back to a third of the way open.
Continuity mistake: When Clark first meets Lois and the staff of the Daily Planet, he is wearing a handkerchief in his suit pocket. After using it to wipe up the spill from the soda, he stuffs it loosely back into the pocket when he exits Mr. White's office. A couple of shots later, it is neatly folded back into a triangle. (00:53:15 - 00:54:15)
Answer: Just to clarify: Superman didn't spin the Earth backwards. We just see the world turning backwards when he went back in time. Of course this doesn't answer your question and it shows how difficult it is to write a good time travel story that doesn't leave the audience thinking of better ways to solve problems.
I guess the way they wrote it, Superman got to be the hero and also get the girl, not really too bad of an outcome.
briggs