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: When Nancy is running up the stairs in her house to escape Freddy for the first time her foot hits the steps and go through the steps into some goop. Look at the steps above that step and you can see the pre-cut holes where the next sets of goop will be. (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: When Daniel is running from Johnny and his gang after the bathroom incident at the dance, there's a lot of fog outside. If you look at one of the trees in the background, you can see that all the fog is being puffed out from behind the tree - obviously a fog machine.
Revealing mistake: Trish jumps out the window and lands face up on the ground. You can plainly see it's Kimberly Beck's stunt double. She looks nothing like her. (01:21:35)
Revealing mistake: When the TVs explode, the glass is very fake and "cardboardy".
Revealing mistake: When the professor is trying to find the gremlin, he is in the room with the movie playing. The projector that is playing the movie is actually moving backwards. (00:44:35 - 00:47:35)
Revealing mistake: There are two Ewoks Wicket's parent is in search of. One of the those Ewoks is climbing down a mountain and the other has finished climbing down. As this happens, look at the Ewok not climbing. As he bends down, half way down his left leg, there is some sort of fold there. This is mainly due to the fact that the Ewok actors wore costumes whilst filming. The fold is coming from the Ewok costume. (00:07:50)
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: When Harkin Banks almost loses control and skis through the lodge, the jump ramp is visible as the woman opens the door. (01:29:45)
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: Watch very closely when the horse is waking up Atreyu. It seems to be searching for something behind Atreyu and then you see a sugar cube fall out from behind him.
Revealing mistake: In the scene with the motorcycle riding on its rear tire, skid marks can be seen from previous takes.
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 Carolyn and the Geek are in the parking lot across from her church, Carolyn gets some help as she climbs over the side and out of the Rolls-Royce - as opposed to using the door. As she makes her way over the side, you can see that she steps onto a step-stool or similar above-ground block before stepping down once more with her next step onto the pavement. There is no such step on the car itself.