Revealing mistake: When Luke is being fed to the Rancor, in Jabba the Hutt's dungeon, there are black outlines around the beast's legs, from the composite's blue screen special effect. This was edited out in the special edition rerelease.
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.
Visible crew/equipment: Right at the start of the film as the alien spacecraft is landing on the planet, you can see the scaffolding of the studio at the top of the screen.
Visible crew/equipment: As the priest is loading his luggage in the car, a large light is reflected in the quarter panel. It is not the sun, as that is ahead to our right while the light is behind us to the left. (00:51:20)
Factual error: Part of the movie takes place in Vienna, Austria. Although the number plates of the cars are like those in Austria at that time, neither the road markings nor the street car which can be seen when both Steve Martin and Kathleen Turner are "climbing" outside their hotel look like those in Vienna.
Factual error: When the Brainstorm project is taken over by the sinister military operative Landan Marks, he begins weaponizing the brain-interface technology and testing it on the human guinea pig Gordon Forbes. As Gordon is subjected to increasingly difficult fighter-jet simulations, Landan Marks gleefully exclaims to military observers, "Now watch this! He can take a full 10-G rollout without losing control, just by thinking about it!" In the flight-simulator cockpit, Gordon grimaces, but the Brainstorm device allows him to remain conscious and maintain control despite his physical distress. But the fact is that no flight simulator in the 1980s or even today would be able to simulate extreme G-forces as described in this film. In fact, flight simulators then and now can't approximate even low G-forces. Only a giant centrifuge can produce such forces; but Gordon is not in a centrifuge for this scene. It's simply a flight simulator.
Continuity mistake: In the airplane, the window shade in the seat next to the main character repeatedly opens and closes between shots.
Continuity mistake: At the wedding ceremony, Prince Colwyn extinguishes his flame inside the basin of water. However in the next shot his baton is aflame again even though he only just put the fire out.
Factual error: SAC's airborne command post is shown in several scenes. Problem is, while there is such an aircraft, it is not a KC-135 Stratotanker, which is what is shown.
Revealing mistake: During the brawl in the 'saloon', the protagonist frees himself from the predicament that had him with a knife pointed at his throat. Cut to one of his friends who punches away one baddie, parries a strike and then "punches" someone else. Sarcastic quotes are needed here, because the straight punch misses its target. (00:44:35)
Continuity mistake: Hawk gets shot, and the stain is on his upper left chest. A new scene shows the stain on the right chest.