Revealing mistake: In the scene where Axel throws the art dealer's henchman onto the buffet table, if you watch carefully (or use slow-mo) you can see the stunt double pulling off that manoeuvre. There is also a stunt double being thrown over the table.
Revealing mistake: When Indy and Willie jump out the window at Club Obi Wan, just as they crash through the glass note the white stunt leggings/knee-pads on Willie's legs above her shins. Willie's legs are bare when she lands on the lower awnings.
Revealing mistake: There is a shot from the Terminator's POV, before he rams the blue car with the semi truck, in which you can see that the car is already damaged. No slow-mo is required to see this, but it is a blink-and-you'll-miss-it shot.
Revealing mistake: When Michael Douglas attempts to swing on a vine over a deep abyss, the rock that he runs into on the other side moves like a marshmallow, indicating that it's a fake rock. (00:39:10)
Revealing mistake: There's a scene where Dana's building is falling apart and stones and stuff are falling to the street below. One of the huge boulders bounces off a wooden police barricade in the bottom left hand corner of the screen, and then off a person. (01:29:14)
Revealing mistake: Conan and his party flee from the temple guards and escape into the crypt, closing the huge stone door behind them. A moment later, the camera shows the leader (Ferdinand Mayne) standing at the foot of the steps holding a torch. He chucks the torch out of sight to his right and begins walking towards the door. If you look closely you'll see the torch disappear nicely out of sight behind the wall as if he had "passed" it to someone standing there.
Revealing mistake: During the invasion of Dune by the Harkonnen, a Sardukar soldier throws a guard from what appears to be the palace's wall. When he hits the ground all the bodies around him bounce as if they where lying on some sort of cushion. (01:09:50)
Revealing mistake: When the guy on the horse pulls out his sword, he has trouble getting it out of the sheath at first and it bends severely. It is clear that it is not a real sword.
Revealing mistake: The opening chase has a police car chasing a white Countach. We hear two officers talking to each other. There are times they are talking to others on the radio, as well. But every shot that allows us to see inside the patrol car, only a driver is in it. (00:04:15)
Revealing mistake: When Supergirl flies through the window to fight the invisible monster, half of the screen shows her jumping in a school uniform and the other half exiting with the Supergirl outfit. Watch closely and you'll notice that her halves don't match, giving the sense that she is missing part of her body.
Revealing mistake: When Kirk and Kruge are fighting, a piece of the cliff breaks away and wiggles down the side of the cliff rather than falling like a rock. (01:22:55)
Revealing mistake: When Col. Tanner is on top of the Russian tank, he is firing his pistol into it. After a few shots, you can see that the slide on his gun locks back, showing that the gun is empty. Tanner does not reload, but is none the less able to keep shooting afterwards. (01:11:25)
Revealing mistake: When the sheriff is going to whip Sarah, he tells her to take down her drawers. Bad editing, you see her hand reach back and make the motion as if she is pulling down her panties but it is visible they are still up.
Revealing mistake: In the opening scene where the alien car is pulled to the side of the road by the cop you can see two identical sets of tire tracks in the dust in the same place - a sign that this scene was filmed more than once in the same location and the filmmakers didn't wipe away the tracks. As the car pulls out you can see another set of identical tire tracks further up the road as well.
Revealing mistake: When Chocolate Mousse throws the anchor with the rope attached into the air, if you watch the ground when they run away, you can see that there's suddenly a lot more rope there, revealing that it was filmed in two takes and the anchor wasn't really thrown directly above their heads. (01:11:20)
Revealing mistake: During the movie, the ninja crushes with their bare hands a golf ball (in the opening fight) and a billiard ball (in the fight against Case). Both times the ball is replaced by a shell filled with talcum powder. It's especially conspicuous in the case of the cue ball, because the previous 'stunt' involved slicing one in half and the ball looked nothing like the one she 'pulverizes'. (00:04:00 - 00:38:35)
Revealing mistake: As the biker punks roam the streets disturbing shoppers and merchants and endangering people sitting quietly at the cafe tables, the majority of the extras are actually laughing and having a great time even when they are yelling and waving angry fists. (00:14:40)
Revealing mistake: As the stars speed up due to the star drive, you can see them shining through the solid part of the door.
Revealing mistake: When Jake is driving his car to run down Vince, there is a quick shot just before he hits him that is obviously a dummy placed in front of the car.
Revealing mistake: When Melvin jumps out of the window, the person who falls out isn't actor Mark Torgl but a stunt double.