Continuity: When Superman lands in Ross's attic, a chair moves to the left between one shot and another.

Continuity: The second hole Gus makes with the axe on the laser ball is smaller a second later.

Continuity: When the roller-skate girl grabs the trolley, the cups and food on the upper plate fall. A frame later they're all back on.

Continuity: Before Superman fixes the Pisa tower, the Italian seller is seen holding a statue by its base. A frame later he holds it by the side.

Continuity: When Clark is waiting for the steel lid to crush him, he raises his arms up. In the next angle they are down and close to his side.

Continuity: When Gus takes the tablecloth off, he walks on top of the fallen stuff to talk about Superman, and then the amount of stuff left behind keeps changing between shots.

Continuity: When the bus to Smallville pulls over, the red ambulance passes by twice.

Continuity: After Clark kills bad Superman he rises and the shot changes. His tie knot is now tilted to the right.

Continuity: When Gus jumps out of the terrace, he has no skis on. When he lands he has them on again.

Continuity: Amount of snow on the railing changes after Gus flies through with the skis.

Continuity: When bad Superman punches Clark, he lands half a meter behind a red car hood. In the following shot the hood is by his side.

Continuity: Before Gus gets on the skis his shoes are grey with thick black stripes. When he lands he has plain brown shoes.

Continuity: The two firemen pointing at the lake are standing close to each other. In the wider angle they are much farther away.

Revealing: In the scene where the two Supermen are fighting, towards the end Clark chokes baddie Superman. In this shot you can see where they cropped a stuntman's hands in the place, where Clark's hands would be, in order to have Christopher Reeve play both parts.

Deliberate "mistake": During the supercomputer's destruction, the 3 electrical probes that are sending lightning to the overhead pylons to draw electricity from them are no longer flashing. So where is the electricity coming from to sustain the computer's lighting system as the fluorescent tubes are still working?

Continuity: When Vera is getting sucked into the computer, she has white gloves on. Seconds later, during her robot transformation, there is a full screen close up of her hand without any glove. Then, when Vera emerges from the wreckage of the computer a few minutes later, she has her gloves on again.

Factual error: When Richard Pryor is working his job in the computer room his boss walks up behind him and is amazed at a program that Pryor has written. The boss asks how he did it; Pryor answers that even he doesn't know. Look at the computer screen - Pryor's amazing computer program is just a bunch of worthless print commands that print sentences onto the computer screen; it serves no real function whatsoever.

Continuity: When the roller-skate girl grabs the trolley. In the close ups she is bending to the front, in the wide ones standing straight.

Continuity: 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: During the credits, a red and white pole with a light on top appears to the right of the crashed green car.