Deliberate mistake: Otis was portrayed as an albino in House of 1000 Corpses, but in this film, he has normal skin pigment.
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: When the captain jumps towards Scott, the distance between the two rows of seats is three times bigger than the other rows shown, obviously to allow for the fight, but still really weird when you look at it.
Deliberate mistake: When Ami's school friend is killed, a short sword is stabbed into the top of her head. Less than a half-second later, we see her face is totally coated in blood, and she gurgles even more blood before dying. There simply has not been enough time for such a volume of blood to have dripped down her face.
Deliberate mistake: In the link between the movie reel and nightclub scenes a train goes past. While the sound effect is convincing, the video has been reversed. The headlights on the train give it away, but cars under the bridge are also seen in reverse. (00:27:55)
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: The photographs that Angela takes off the boys that show the girls naked obviously were not taken outside the cabin, they are far too clear. The fly netting and window would have obscured them. Also, judging by the position of the beds in the photographs it seems like they were taken inside the cabin. (00:32:02)
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: 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: 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: After the AN-12 launches from the carrier, you see U.S. Navy near the nose of the craft, and MG on the tail code (MG=McGuire Air Force Base). Also, during the flight shots, the plane transforms between a C-130 and AN-12 multiple times.
Deliberate mistake: The video feed from Jill's laptop doesn't match the angle we see her laptop in. The image should be a weird, low-angle shot with lots of space above her head given her laptop is down on her lap, but the image we see is a pristine parallel shot. Additionally, the video footage is way too high quality for a 2013 laptop webcam. (Heck, it's too high quality for a 2024 laptop webcam.)
Deliberate mistake: In the opening, the kids are looking up at the floor boards. Uniform light seeps through, but as it turns out, the house was small and swarming with an angry mob carrying torch. The light is not really compatible with that scenario, and in fact when the scene is shown later again, the lights are warmer and you can see the torches flickering. It's most likely a trick not to give away exactly what was hunting the kids in the basement. (00:01:00 - 01:11:20)
Deliberate mistake: The wrecker used in this film is a Western Star Model 4964. The manufacturer emblem (a chrome 5-point star superimposed on a large "W") is normally displayed at the top-center of the truck's radiator. Apparently, the film makers could not bring Western Star on board for an advertising agreement, or Western Star specifically objected to their logo appearing in the movie, because the Western Star emblem on the wrecker's radiator is carefully kept out of frame or otherwise obstructed from view throughout the film. For scenes in which a full frontal shot of the wrecker is unavoidable, the Western Star emblem is very deliberately covered up with dark green tape.
Deliberate mistake: The snacks in the vending machine were almost to the top of each display shelf, but an interior to exterior view showed the lab researcher's head unobstructed and a foot or so clearance between the snacks and the top of the shelf. (00:06:30)
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.
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: When Tree turns on the magnetic medical equipment, it's somehow strong enough to yank a big, heavy wheelchair up and pin Gregory in only a split-second, but not strong enough to instantly pull the screwdriver out of Tree's hand? Obviously this was done so Tree could have a cool moment where she lets go of the screwdriver and it impales Gregory... but it makes no real sense.
Suggested correction: It does make sense. The wheelchair wasn't secured and contained lots of metal, so it was immediately pulled towards the scanner. The screwdriver had a lot less metal, and Trew was holding it very tightly, and she knew what was about to happen, so she should strengthen her grip even more, allowing her to keep hold of it.
Preposterous. Depending on how they're set, MRI magnets can yank entire hospital beds clear across the room, and even once killed a man by setting off a concealed gun he was carrying. There's no way she was holding onto that thing.
Deliberate mistake: The Janitor was driving away from Willy's but the explosion shows up in the front of his sunglasses. (01:21:47)