Visible crew/equipment: When C-3PO is on the conveyor belt, if you look in the reflection in his head you can see the camera crew. (01:26:40)
Continuity mistake: The egg timer in the jail is about to run out, but when Dale runs over to it and tries to turn it over, there is more sand in it than before.
Deliberate mistake: Has there ever been a more obvious body double than the one used for Angie Dickinson in the shower scene? Not only does the top of every shot stop right at the collarbones, she is much taller than Dickinson, she has a much deeper tan and (of course) her breasts are much, much bigger.
Visible crew/equipment: When Harris and the two Irish men have been killed at the end and the car crashes on top of the other the ramp used to make it fly is visible.
Factual error: A film about the making of a film. A car is filmed going off a bridge, and the footage is played back repeatedly. Throughout, the car is referred to as a Duesenberg, even though, in nearly every shot, the Mercedes tri-sected circle logo is visible above the radiator.
Revealing mistake: In this very-low-budget but star-studded flick about UFO contactees and cattle mutilations, Jan Michael Vincent's semi-auto handgun runs out of ammo during a firefight after firing only 3 rounds (the slide locks open, indicating the magazine is empty). Without reloading or racking the slide, Vincent continues firing 5 more rounds; but we see again, in close-up, that the slide is locked open, indicating an empty magazine. (01:00:55)