Deliberate mistake: It's a humorous twist that Randy's killing is covered up by some random guys passing by with a ghetto blaster, but there was dead silence when Randy was talking earlier; not being in frame does not block soundwaves. (01:05:15)
Deliberate mistake: Several times, you see an exterior shot of Nathan's house, and it is very clear that it is the same shot being used over and over, sometimes reversed.
Deliberate mistake: While walking bare-footed in the barn looking for RJ, Wayne does not raise his feet very high - that is, until he is about to tramp on the nail that is perpendicular to the floor. If Wayne had kept walking like he had been, he might have bumped into the nail or object holding it up, but not got punctured by the nail. (01:06:40)
Deliberate mistake: When Ben is discussing boarding up the windows to Tom, he says he still needs to get a few spots upstairs. Why would he need to board up the upstairs windows when the zombies have no way of reaching them?
Deliberate mistake: After Venom eats the head of one of the Drake's henchmen there is no blood from the wound.
Deliberate mistake: When they are listening to the tape, Cheryl yells out and shuts it off. Scott says he wants to hear the rest of it, but then deliberately fast-forwards it a bit before starting it playing. If he wanted to hear the rest of it, why does he skip part of it? This allowed Cheryl to shut it off as soon as she finished her line/action, but then Scott could fast-forward it past a mark on the visible reel-to-reel tape so it would start immediately on the chanting rather than in the middle of the lecture where Cheryl stopped it.
Deliberate mistake: When Margo is in the Superstition exhibit, she thinks she hears/sees something and runs for her life. She gets into the women's bathroom and tries catching her breath before the mirror. Hearing a noise outside of the bathroom, she goes into a stall, locks the door, and stands up on the toilet so her feet don't touch the floor. It was just a little old maid washing her hands outside the stall, and the strange sound Margo heard was the maid using her inhaler. However, how is this little old lady - with asthma, we can assume - supposed to have gotten all the way from deep inside the exhibit to the women's room within seconds, pushing a big heavy cart? Why would she even be in such a hurry? We can assume, however, that perhaps this was a deliberate mistake to show that, after all, maybe Margo wasn't just freaking out over nothing...that perhaps something was in the exhibit with her.
Deliberate mistake: This mistake was admitted to in the DVD commentary by the director. When at the embassy, once they open the window, the camera pans up to show a destroyed helicopter on top of the building. This is a mistake as in Moscow, it is restricted airspace for helicopters, with none at all for any purpose to be allowed to fly over the city, not even to land on the American Embassy. However, the director really wanted the visual of a destroyed helicopter on top of the building so added it anyway. (00:41:49)
Deliberate mistake: Blood does - but should not - drain out of deceased Mitch's mouth when he is placed on the couch and his head falls over because Oliver gets up. (00:30:10)
Deliberate mistake: When Kyle goes through the windshield, the windshield shatters like tempered glass. Windshields at the time were made of laminated glass.
Deliberate mistake: Abraham is sitting to the right of and slightly behind the cross he hammered into the ground, but is about 3' away. When there is a close-up, Abraham is much closer to the cross - the end of the crossbar to the right is directly above his shoulder and his knees appear to be close to the vertical bar. (00:45:15)
Deliberate mistake: The chainsaw cuts off the German torturer's leg and it manages to move all by itself a few feet within a few seconds, when it would just run and slowly move and stall as seen after it moves. Obviously done to increase the tension. In addition, the chainsaw looks very clean with no blood dripping and bloodstains on the floor.
Deliberate mistake: The oval mirror was in a depressed wall yet was able to reflect a window within the adjacent depressed wall. (00:18:23)
Deliberate mistake: Helena asks Justine over to watch Atonement, but she instead goes on her 'date' with Alexis. When the scene cuts to Helena and Emily watching the film, it's actually The Duchess.
Deliberate mistake: When Chad picks up the cop's gun and fires at Dale and Tucker, the bullets hit the wooden wall. Wood doesn't make ricochet sound. (00:41:45)
Deliberate mistake: There is a wooden chair upside down on the floor, with legs that angle outward. Jack Cain is able to pick up a party-goer, throw him down from over his head, and spear the party-goer on the right side with two of the chair legs. The chair legs are still angled outward but will break off to the side from the force of the party-goer's back hitting them. (01:07:17)
Deliberate mistake: When the cannister rockets through the ceiling window, the pieces of glass from the initial impact never fall down. Nor are they on top of the window in the next shot. They just sort-of vanish. Additionally, the cracks don't match from the first shot to the second time we see it. There's suddenly less cracks which is odd because it's a digital effect.
Deliberate mistake: During his autopsy in Saw IV, it is revealed John Kramer was 52 at the time of his death. Kramer's role in this film is the very early stages of his time as Jigsaw, shortly after his cancer diagnosis, which would put him in his early 50's. However, he looks far too old to convincingly be that young (Tobin Bell was in his mid-70's at the time of filming). He even looks older than he did when he was on his deathbed in Saw III.
Deliberate mistake: Hansel will die if he doesn't take his medicine for 4 hours, but after hanging overnight in a tree he shows no signs of needing.
Deliberate mistake: When Brody confronts and then flees from the Headless Horseman, the horses never break into full gallop (it's little more than a stiff-legged canter), which is odd for a life-and-death chase with the bloodthirsty Headless Horseman in murderous pursuit. This was probably done on purpose, for safety reasons, since the actor playing Brody was performing his own stunt riding at night. To cinch the illusion of a real chase, audio was added of a 4-beat gallop.