Revealing mistake: Bruce Willis wore fake feet during the movie to protect his own while shooting the film. They were like boots that slipped on over his. At the part where the FBI guy shoots at him from the helicopter and Bruce jumps to a lower level of the roof, you can see the tops of the fake feet that aren't tight around his ankles. (01:50:30)
Continuity mistake: When Maggie starts cleaning up the flour, she hears a noise and looks at the three blue flowerpots, and there is a wooden chair right beside them. Then when it cuts to Maggie getting up, the chair is now about a foot away from the flowerpots. (00:22:50)
Continuity mistake: In the scene where Roger and Hoskins are moments away from crashing into a bridge in the cab quickly look at the road there is no gate in between the roads. But when they jump onto the bridge they crash right into a gate. (00:57:15)
Continuity mistake: When Kristen meets the little girl drawing the chalk house, between the two shots before it starts raining, the chalk drawing changes. (00:02:35)
Continuity mistake: In the basement of the Orpheum theater, Holmes takes a lamp off of a wall and places it on the floor. The shot cuts, and the lamp is back on the wall. When the shot cuts again, the lamp is back on the floor. (01:29:25 - 01:30:45)
Visible crew/equipment: When Drebin chases the doctor out of the hospital, the doctor gets a car, while in the background, Drebin falls from the ladder. Drebin then emerges from under the car. The doctor drives off, and Drebin enters the foreground. Look in the windscreen of the car Drebin emerged from. The top of a man's head with grey hair appears at the end of the shot, thinking it's over. This is the stunt double that dropped from the ladder. (00:32:25)
Continuity mistake: When Mac's on the windshield and the car starts to dodge cars, one shot from inside the car shows the alien has disappeared.
Continuity mistake: When Garfield is in outer space asking the computer to tell him if he's really living in life number 9, his armchair vanishes for an entire shot. (00:40:00)
Continuity mistake: When Delia spray paints the word “mauve” on the wall, between shots it is apparent that the script of the word changes. One example would be that in the first shot the tops of the letter “M” are pointed, like triangle tips, but in the next they are more rounder. The writing also moves lower on the wall. (00:15:50)
Revealing mistake: When the Blob is eating Paul at the doctors office, his right arm is the only part not covered. It's very obvious that it's in a fixed plastic sleeve surrounded by the Blob's ooze.
Continuity mistake: When Sykes is at his desk monitoring Fagin from a security camera feed, Dodger suddenly appears onscreen between shots, right beside Fagin. (00:51:00)
Continuity mistake: When Valmont is waving the letter behind his back, in the closeup the address is facing upwards, but in the wider shot we can see the wax seal is now visible.
Continuity mistake: Near the end when they're entering the Mexican village, Billy's coat disappears as he rides through the gate. (01:17:45)
Revealing mistake: In the barber shop scene at the end of the film, Agent Anderson terrorises Deputy Sheriff Pell (who has a full head of hair) with a razor blade. Anderson throws him across the room, but the person being thrown across the room has a mostly bald head.
Continuity mistake: John Heard's racquet jumps from one hand to the other when he and Tom Hanks fight on the tennis court. (01:17:20)
Continuity mistake: When Dr. Loomis is thrown through the window by Michael Myers in the school notice that Myers' hair has strangely turned white. The next scene Myers' hair has gone back to being brown. This is more evident in the widescreen version. This is because during the hectic shoot, an unfinished mask that wasn't painted or dyed yet was accidentally grabbed by a crew member for that one shot. It wasn't caught until the film was being edited. (01:13:50)
Continuity mistake: Throughout the film Elvira wears her trademark black dress, split to the top of her thigh, and underneath it she always wears black pantyhose. Inexplicably, this changes to black stockings and suspenders when she is undressing for bed on her first night in her new house. (00:31:35)
Visible crew/equipment: When they're building the petticoat balloon, the camera slowly goes back. Look at the lower-right corner of the screen: there is a man wearing a stadium jacket. He's a crew member.
Continuity mistake: When General Kael takes the baby to Nockmaar Castle, it has an extra 'turret' on the left-hand side, which has disappeared when Willow and Fin Raziel face the castle later on. (01:31:40 - 01:41:15)
Continuity mistake: In the scene where Bill's old boss comes back to see him notice when Bill shoots him and takes the drink. All of the drink comes out of his chest because of the bullet holes. Well notice his shirt is all wet, then in the next scene when he takes off his hat his chest is all dry.