Deliberate mistake: After trying to get away from the monster, Costello finally unties the boat as Abbott rows away from the burning dock. The next shot of the boat has Abbott slowly rowing the boat, but you can see it's not moving as there's no wake, and when they jump off the boat after the Invisible man speaks, it doesn't rock, meaning the boat was mounted to something to prevent any movement, so they could make the jumps into the water.
Deliberate mistake: Candy tells her radio listeners, "Our phone number is 201-5137." Assuming the radio station's reception extends beyond more than a small geographic area, an area code is needed for callers outside of the immediate area. On Ellie's cell phone, Mary's number shows up with an area code. (00:05:55 - 00:07:20)
Deliberate mistake: The disco ball doesn't start reflecting the sunrise until after the lead characters get out, even though it should have began to reflect light right when the door opened.
Deliberate mistake: The blades on the tiller or harrow (?) were only a few inches apart when Burkett was falling back onto them, but only one blade went through his chest. Burkett's body was wide enough for at least three blades to penetrate. Also, the blade appeared to be exiting in the center of his chest (along the button line of his shirt), but the close-up showed the blade to his right. (00:19:40)
Deliberate mistake: When they're watching the footage of the tsunami hitting Cannon Beach, Sabrina turns the TV off as the shot pulls backwards. Suddenly, the glare on the TV appears out of nowhere.
Deliberate mistake: When Dead Reckoning is firing the missiles at the end (towards the crowd that's being eaten by zombies), you can tell that they repeat the same shot of the missile firing three separate times, even though it's supposed to be three different missiles. (It's the shot of the exhaust coming out of the back of the launcher.) They try to mask it by cutting a little earlier or later each time... but it's obvious.
Deliberate mistake: In the whole of the 'Psycho' series, there has never been a closet door next to the dress cabinet in Mother's room, but for this movie there is suddenly a closet.
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.
Deliberate mistake: The images of Spencer's face in the driver's side mirror are not realistic for someone in the driver's seat. The driver's side mirror is angled outward (perhaps 60° beyond a typical angle), but his face is perfectly reflected. When Spencer starts smoking, the viewer gets a glimpse of a figure behind his car. Spencer senses something and his face is shown backwards in the mirror, as if he were crouching outside a few feet from his car. Spencer does not use the more practical rearview mirror. (00:19:11 - 00:19:47)
Deliberate mistake: The legion of hellspawns during the film's climax are merely copied and pasted throughout the screen, as evidenced by the fact that many of them perform the exact same distinguishable body movements, such as pacing right and left from a crouched position.
Deliberate mistake: Frequently during the movie, British surgeons are referred to as "Doctor". In Britain, surgeons are always referred to as "Mister"; this is a hold-over from the surgeon's non-medical past (barbers, etc). This would likely be confusing to American audiences.
Deliberate mistake: When the scanners escape the apartment in the van and the assassins are in pursuit there is a street view shot of the assassins driving up next to the scanners' van. If you watch the street on the right side of the screen you can see people stood watching the filming in groups, out of harms way. (00:50:28)
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: There is one vertical board missing between the other parallel boards, but the upper half of the gap is wider and forms a "V" when Mark is videotaping Jenna (who is on the other side of the fence). The missing board, between two parallel boards, has a uniform width from top to bottom. (00:08:40)
Deliberate mistake: When Tiffany is reading the self-help book for recovering addicts, there's a closeup of a page. While the headline for the chapter makes sense, the body text is completely unrelated and is about corporate work culture. (Likely just some generic free text the prop department copy/pasted into the book prop.)
Deliberate mistake: The doctor appears to write just three numbers or a short wavy line on the back of his business card for the phone number he told Marjorie to call (to get a second opinion about Nathan). (00:42:35)
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: 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: After Sam freed Gary from being tied up by the aliens, Gary pulled off the cast he got earlier that day and was able to use his left arm as though it had never been broken. (00:45:43)
Deliberate mistake: After Ryan and Michelle finish changing the flat tire and are surprised by Leatherface, he chases Ryan around the back of the car and smashes the windshield. At the moment the camera is in the backseat shooting out, we see the chainsaw with the chain popped off and hanging. My best guess is that it was done intentionally (for safety reasons) because the saw was close to Ryan. The crew must've been too lazy to completely remove the chain and just popped it off the track instead. (00:25:25)