Other mistake: The clocks as we learn later in the film stop at 03:07 due to that being the time the witch died. However, the grandfather clock we see for the first time has stopped at 03:07. We then see it stop at 03:07 the next night too. However the minute hand is in a different spot to when it first stopped - it should have stopped at precisely the same point. (00:13:05 - 00:18:50)
Other mistake: Everytime it shows a window it is morning, even if the scene is supposed to be at night.
Other mistake: When the family's car is being hit by the ambulance, we see Gerry's head bouncing around by the impact in a close-up. Camera angle is from inside (approximately from the centre armrest). We see out his window, and there is nothing there. The camera angle changes to an exterior shot, and its clear that the position of the ambulance hitting the car should have made the ambulance visible from the interior camera. (00:08:05)
Other mistake: When Odd Thomas and Stormy are riding on his moped through town to stop the massacre they pass a car dealership. All of the letters on the dealership signs are reversed except for a large lighted awning sign that says "Welcome to quality." The normal and reversed signs appear at the same time in the same frame. (00:48:00)
Other mistake: After the bridge rescue, when the wind picks up the letters of the Hollywood Sign are uprooted and take flight, and we see the "Y" flying through the air, but later when they're driving away we can see Mt. Lee behind the car with the remaining letters, and the Y is still mounted there.
Other mistake: After Carrie levitates herself and goes outside, there's a wet spot on the concrete that's the size of both her feet, showing her landing spot from previous takes.
Other mistake: This is hard to describe. When Nica finds Jill's dead body, you can see the side of her wheelchair and feet on the right side of the screen, and they've been laid over the top of the image in post-production. Their angle literally makes no sense. Her chair would have to be leaned 45 degrees to the side for the shot to be possible. Jill also wasn't close enough to the door where Nica is for the shot to be possible.
Other mistake: In final 14 minutes, the greys are attacking the house. Several screws are "unscrewed" from the plywood. The first two are turned the wrong way, and the sound effect is of tightening. (01:23:54)
Other mistake: Throughout the film, you can frequently see many people's faces blurred, phone numbers blurred, store-fronts blurred, etc. This is because the production could not afford the rights to show these people, places and things, and simply blurred them out.
Other mistake: When the security system is armed, you can see the barricades are smooth steel panels running inside the outer walls, obviously on runners. Now, how do you attach a chain to a smooth steel panel and how do you rip it out without bringing the whole wall down? When Charlie lets the fugitive in, the panel is at least 1in thick. There is absolutely no way anyone is getting through that without specialised tools or heavy machinery.
Other mistake: Ten minutes into the movie, during the credits one character is presented as "Cheno", but in the end credits he's "Chino". (00:10:35)
Other mistake: When the title card "FLYING MONKEYS" appears on screen, during the opening fly-over shot, if you look near the bottom right of the screen you can see something briefly move into, then out of, shot. (00:02:28)