Short Circuit (1986)

Revealing mistake: When Number 5 is leading Number 3 into the toilet and moves at the last minute, you see Number 5 falling over, but in the next scene, he's perfectly fine.

Revealing mistake: When Frank takes the orange juice from the tray Johnny 5 is holding, the tray moves with the glass for a second. This is because the orange juice glass was glued to the tray, so Johnny wouldn't drop it. (01:05:25)

Revealing mistake: After Johnny blocks the gunshots from Frank, he begins to flip a coin and imitate John Wayne. You can see the thin wire connected to the coin on the left side of it.

Revealing mistake: Some shots used in the scene where Johnny runs from the Nova helicopter were shot using the small toy version of Johnny. There were no mountains in the area and a small version was filmed heading towards some big rocks with the camera on the ground to give the impression they were in a mountainous area. (01:30:15)