Revealing mistake: Gracie hugs the Russian waitress in order to have a better view of the disc hand-off appear on the monitor. As she raises her left hand that holds the book/camera lens, we see that the digital feed that appears on the monitor stays steady and level, even though she is raising the book/camera lens higher and closer to her face. Obviously the feed that we see on the monitor is not taken from the book/camera lens. (00:04:10)
Revealing mistake: You can see the plane intact even though it has exploded. It stays complete, there's just fire around it. (00:18:55)
Revealing mistake: Jennifer swipes her card the wrong way at the studio and the door opens anyway. (00:57:15)
Revealing mistake: When Bruce Willis is in the hospital, the doctor comes up to him and asks Bruce to look at him. The doctor proceeds to get a torch out and shine it into his eyes. Yet there is no light coming out of the torch. (00:10:25)
Revealing mistake: Many times throughout the movie, people are shot and they bleed, but their clothes don't have holes from where the bullets hit them. The most noticeable examples are when the teacher is shot at the end, and when the big gun fight between the girls breaks out in the lighthouse.
Revealing mistake: When Jean Reno and Vincent Cassel approach the hanging body of Jean-Pierre Cassel in the doctor's house, the hooded killer can be seen standing to the left of the screen. [Not visible on the VHS version, but on the widescreen DVD].
Revealing mistake: In the first morgue scene the body on the table is obviously breathing.
Revealing mistake: When the guy with the hand missing is playing his guitar, you can see his actual wrist bending underneath the fake arm that covers it.
Revealing mistake: In an early shot shown from the neighbor's house, it is established that the Spencers' house is quite a ways uphill. Some of the later shots where Claire is spying on her neighbors and looking at their home, the angle of view does not appear to be correct. The neighbors' house looks like it's a lot closer and more level with the Spencers' home.
Revealing mistake: When the "dudes" are taking out a load of bin bags, you can see through the lighter coloured ones that they are actually filled with polystyrene chips (the packing kind) rather than any litter.
Revealing mistake: At the 'beginning' when Teddy and Leonard drive up to the abandoned building with the old truck out front, inside the truck Leonard handles a number of .357 revolver calibre bullets that have apparently not been fired, but you can clearly see the indented primers in the base of the bullets, indicating that they are just inert movie props. (00:04:40)
Revealing mistake: The 7 Children on the road that Kim swerves to avoid and dents the car are obviously wearing facepaint - and it's been applied very badly at that.
Revealing mistake: In the close-ups of the elves during the Coronation Ball, you can see the fishing wire used to attach their wings to their backs.
Revealing mistake: When Jessica's dead body is seen by Annie in her bath and then in the hall, the make-up that is keeping Jessica's eye shut is coming away around the edges.
Revealing mistake: When Patrick opens his fridge to offer Jean some sorbet, you can see the decapitated head of a woman in the fridge. If you pay close attention, you can see the head is moving a little. (00:59:36)
Suggested correction: It's a prop head resting on a freezer shelf. It could simply be that opening the freezer door causes the head to sway a little, similar to if you had an egg, lemon, or something else that didn't have a flat bottom resting on a shelf inside a fridge.
No, the way it was filmed was with the actual actress putting her head up through a hole in shelf. It's her head moving.