Revealing mistake: When we see Dark Helmets' hoverjeep in the desert, watch the front end: you can clearly make out the edge of the mirrored box they used for the "hover" effect.
Continuity mistake: When the statue of Liberty is about to crash on the street, a close shot is seen of jammed cars and hysterical people. When the shot changes to Superman flying to the rescue, the jam, the cops and the people have disappeared, and all is nice and quiet in Metropolis.
Revealing mistake: In the scene where they're tumbling down the hill, Buttercup has a beard.
Continuity mistake: When Owen arrives at the hotel to meet Neal and Del to drive them to the train station, Owen is wearing gloves on both hands. As he introduces himself and shakes their hands, Owen's right hand is now bare even though there wasn't enough time to remove the glove. (00:33:55)
Continuity mistake: After trying to entice the primitive tribe with flashy clothes and a boom box, Alvin and Simon get tied to a hut. The four ropes around their wrists are initially tied together in one knot right above their heads. But once they notice that Theodore is being pampered like a god, Alvin and Simon's wrist ropes are suddenly knotted separately instead. (00:51:05)
Revealing mistake: When Jack is hanging out of the truck you can see him standing on the hood of the car which Lydia is driving. At some points we get camera view from the back seat of the car. In some angles the mirror inside the car disappear. This is to prevent us from seeing the camera. (01:04:15)
Other mistake: When He-Man is fighting against the centurions on the floating disks, he tells the others to get inside a building. As he opens the door to the building, not only does it fall right off the hinges, but his sword also falls right off his back, pulling his cape off with it just as the scene ends. (01:09:20)
Continuity mistake: When Bond has his final confrontation with Whitaker, he empties his PPK at him in an attempt to take him down. In the process, he hits the gunshield on Whitaker's weapon five times and it remains clean. But when Whitaker rounds the corner a few seconds later, the impacts from the PPK bullets are suddenly visible on the shield's surface.
Continuity mistake: Early in the movie, Mac throws the dead green berets' dog tags to Dutch. As he catches them, Dutch has his hand closed in a fist, and the dog tags are hanging to the left. But in the close-up shot where we can read the name, his fingers are more open, with the tags resting in his palm.