Continuity mistake: From the wide shots, the black stripe on the side of the oil tanker is 12 to 15 meters wide, but on the close-up of evil Superman destroying the tanker shows it's thinned to barely a couple meters wide.
Continuity mistake: When Clark is below the steel lid, the shadow he casts moves around depending on the shot.
Continuity mistake: After the truck falls off the bridge, before Superman arrives a red truck passes by a green one and keeps on to the other end of the bridge. When the angle changes, a split second later, the red truck is now several feet back, not running and parked next to the green truck.
Continuity mistake: In the Olympics ceremony, the file footage shows very few people by the final steps to the cauldron. When the shot changes to the modern footage, a lot of people have suddenly appeared there, plus they change bewteen shots.
Continuity mistake: When Ross is reading a newspaper in his office, the black paper clips move around between shots.
Continuity mistake: Before Gus gets on the skis his shoes are grey with thick black stripes. When he lands he has plain brown shoes.
Continuity mistake: When Evil Superman arrives at the oil tanker, the tower on the deck disappears in the close-up where he opens a hole in the steel.
Continuity mistake: When Jimmy takes the picture of the Stokis, he lifts his finger from the camera and raises his head. In the following angle he repeats every movement.
Continuity mistake: The toy penguin that catches fire is already burned and damaged, when it's supposed to come brand new from the seller's stall.
Continuity mistake: When the bucket of yellow paint falls on the old man, he turns around and starts to walk backwards. In the next shot, he is facing forward.
Continuity mistake: The lid that falls on Clark has a bumpy side. One of the shots shows the lid falling with the bump pointing at Clark's head. For the rest of the shots the bumpy part is on the left side.
Continuity mistake: When the bus that Clark and Jimmy are on pulls up to the traffic jam, you can see the smoke from the fire is wafting all over the place. When the angle changes when the two climb off the bus, however, the smoke is limited to the distant view.
Continuity mistake: When Superman arrives at Pisa for the second time, the sky changes from violet to blue.
Continuity mistake: In the bar, while bad Superman is destroying the bottles, the way they are placed and the ones that are broken or undamaged keeps changing between shots.
Continuity mistake: Bad Superman punches Clark and he lands by a car door. In the next shot the door has magically moved on top of him, which makes Clark take it off of him.
Continuity mistake: When Clark is choking bad Superman, his right hand cleans itself after Superman disappears.
Continuity mistake: When Superman lands in Ross's attic, a chair moves to the left between one shot and another.
Continuity mistake: While bad Superman is in the bar, the whiskey bottle's label faces the window. From the window's point of view there's no label seen.
Continuity mistake: On the Grand Canyon, when Gus is about to get on the donkey, the first shot shows him several meters ahead of Vera. The next aerial angle shows him very close and parallel to her.
Continuity mistake: During the credits, a red and white pole with a light on top appears to the right of the crashed green car.
Answer: The only reason that Gus was working with Ross, Vera and Lorelei was because he stole money from the company he worked at. To avoid going to prison, Gus was forced to do anything that they wanted. After realizing that his computer was designed to do anything it was ordered to, including killing Superman, Gus removed a small screw which shut down the power momentarily but, after the computer brought itself back online, Gus attempted to destroy it with an axe to save Superman. Superman saw this and realised he was wrong about Gus and after the computer was destroyed decided to help Gus find a job.
That makes sense, thank you! Been bugging me for years.
Jen Hen
You're welcome.