Other mistake: Towards the end of the movie, when Superman drops Gus off at the coal mine, Gus begins talking with the coal miners about him and Superman. He then rips open his shirt (as if he had a Superman costume on underneath). How did Gus know that Clark Kent tore his shirt like that in order to change into Superman, or keeps his suit under his clothes at all? The only people who know this fact are the ones who have seen the transformation from Clark to Superman, i.e. the audience.
Character mistake: When Richard Pryor is on the computer attempting to formulate Kryptonite to kill Superman, a screen shot of the computer shows the word "recieved." The I and E should be the other way around. (00:59:25)
Continuity mistake: In the junkyard, when Clark takes the iron lid and gets out of the hole, he leans on his right. In the following shot he is coming out again and repeating the movement.
Continuity mistake: After evil Superman makes a hole on the side of the oil tanker, he flies away and we get to see a bird's eye view of the ship. But now the hole is gone.
Continuity mistake: When Gus is falling from the building on his skis the sky changes colour from shot to shot.
Visible crew/equipment: When the evil Superman flies into the junkyard, you can plainly see the wires from the harness. (01:26:00)
Continuity mistake: When Superman enters the acid storage room we have a glance at the temperature needle and we can see it is way to the right; but the chemist is calm and no alerts are active. Minutes later, before the place explodes, while Superman is freezing the lake, the lights in the room turn red and the chemist freaks out, but the needle is further away from the danger zone than it was when we first saw it.
Continuity mistake: When Superman extinguishes the flame on the toy penguin, it looks brand new, as opposed to the worn out look it had a couple seconds before.
Revealing mistake: When Superman gets blown away by the bombs, he is being smashed onto the rocks. You can easily see that the rocks aren't real, but also that when he rises up again, you can see the cardboard rocks dent.
Continuity mistake: In the scene where the blind man picks the painting machine, note that there are some water marks on the pavement going to the right. These are not visible in the next shot.
Continuity mistake: When the penguins are on the floor, a wide shot shows a man picking two of them, each with each hand. The close-up shows his hands empty.
Continuity mistake: The aerial view of the Grand Canyon shows Ross bending over to prepare his flying vehicle. In the next shot he is up.
Continuity mistake: When Superman is getting drunk, he pours some nuts out onto the bar. When it's a close-up, the nuts are many and close together. Next shot, the nuts are more sparse and scattered.
Continuity mistake: In Ross's office, when Gus makes the liquor shelve turn around, the way his jacket is done up changes between shots.
Continuity mistake: During the junkyard fight, the sky colour keeps changing from cloudy to sunny all the time.
Continuity mistake: The diamond Superman makes by compressing a piece of coal would not be cut into a diamond shape like that, and a diamond made from a piece of coal that size wouldn't be nearly as big as it was.
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.
Visible crew/equipment: When bad Superman is bending the glass from the bar, watch the right side of the screen and you'll see the reflection of the cameraman slowly sneaking in.
Visible crew/equipment: When Brad opens the door to Gus, cameras and equipment are reflected in the glass.
Factual error: The supercomputer has the British spelling 'Defence' written on it, instead of the American 'Defense', even though the movie takes place in the USA.
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.