Revealing mistake: In some extended edition cuts of the film, Regan backwards spider walks down a flight of stairs, and blood falls from her mouth. But her face isn't that of Linda Blair, but of a stunt double.
Revealing mistake: When the Grand Ville turns onto the street where the children are playing, it clips a parked car as it makes the turn. This is the same car that later gets its driver's door ripped off by the Grand Ville just before the police give chase. It was repainted red for the second scene, but note the same dent in the right fender as before.
Revealing mistake: When Sinbad and his men are fighting the pagans' "god of the single eye" centaur, Margiana the slave girl is shown screaming briefly. If you look closely, you can tell it isn't Caroline Munro, but a close look-alike.
Revealing mistake: When Han is killed by Bruce Lee, and the door is spinning, you can see the belt that holds Han to the door.
Revealing mistake: When the bad sheriff tries to run Buford Pusser over, he drives off the road and the car explodes for no reason. It's in the air when it explodes, there's no way it could have exploded without hitting the ground.
Revealing mistake: When Tee Hee bends the barrel of Bond's Walther PPK, in the close-up, the score marks where the barrel has been pre-cut are visible.
Revealing mistake: When Maturette dies at the end he cannot close his left eye all the way because of the totally noticeable fake contact lens he is wearing.
Revealing mistake: A metal ramp is visible on the front bumper of the 1972 Ford Galaxie sedan when it rams the motorcycle head on.
Revealing mistake: After the jailbreak, a number of reaction shots for which the shot background is the villagers in the speeding wagon, not only do they not "bounce" with the wagon, they are not even animated.
Revealing mistake: In the scene where Sgt Howie hits McGregor (who is dressed as Punch) with a candlestick, watch closely and you can see that the blow from Howie is aimed into the padded section on the back of the punch costume, rather than at the back of McGregor's head.
Revealing mistake: At the beginning of the film, Stan reverses the bus into the manager's car. While the manager is under the bonnet looking at the engine, causing it to fall on him, you can see a rod with padding on it to stop the bonnet from hitting the manager. It is gone in the next scene.
Revealing mistake: After Hooker escapes the attack by Lt. Snyder in the phone booth, he runs down an alley. On a cross street in the distance, a modern sedan and large white truck drive by.
Revealing mistake: Part of the concept of the film is that, save for Jesus and his disciples, Manhattan is deserted for one day. However, during the baptism scene in Central Park, you can see a horrified man in the lake on a boat, desperately trying to row out of the scene.
Revealing mistake: When Barbara Windsor is fighting Margaret Nolan in the Hotel Lobby, they jump onto a sofa and it falls backwards. If you look carefully, the lady seated on the sofa can be seen helping it fall backwards with her foot.
Revealing mistake: The sliding door to the bedroom in Simonson's apartment appears to be covered with a sheet of 'bubble wrap' in early scenes of the room.
Revealing mistake: When Chino does some rodeo riding when he breaks in one of his horses we get a good view of the stuntman's face. (00:33:50)
Revealing mistake: Right at the end when John is dying look at the texture of his blood. It is way too thin, almost like coloured water.
Revealing mistake: When Eastwood shoots off a portion of the bad guys ear, the resulting portion of the ear is very fake looking.
Revealing mistake: When Jack Hawkins punches through the door it is very apparent that it's made of very thin wood to make it much easier to hit through.
Revealing mistake: Near the beginning, Megalon steps out from behind a mountain. It's obvious the "mountain" is a cardboard cutout.