Other mistake: As the blond punkee pillages the bedroom for anything of value, the unseen giggling/squeaky "doll" voices prepare to attack. She is yanked to the floor by her feet, screaming, as the unseen grab her hands, then proceed to "ram" her face-first into the wall. The large blood spatters do not match the injuries to her face nor her forehead. Also, under normal circumstances, the victim would be rendered unconscious following such force. The punkee is merely a bit disheveled as the unseen toss her outside the doorway. (00:30:50 - 00:31:35)
Other mistake: When Ricky confronts the mother superior in the dining room, Ricky raises the axe above his head and brings it straight down in one single motion. Both Ricky and the mother superior are facing each other. At that angle, it would have been impossible for Ricky to decapitate her. At best her head would have been cleaved in half, but not decapitated.
Other mistake: In the scene near the end when Jackie drives the big truck through the house, there are explosions everywhere, in solid concrete, and huge sparks from tiny wires. And when did thin wood pieces like the wooden tower/pavilion outside start to explode? Nothing modern or metallic was placed on this pavilion, so that can't explain the explosions.
Other mistake: When at sea and during the crew member foc'sle rescue, the ship's crew, including Kevin Costner, are wearing ship ball caps reflecting USS Billings (BB 1369) and the BB represents "Battleship." However they are actually on a Guided Missile Destroyer "DDG 21", the USS Cochrane, as indicated by the hull number 21. (00:15:00 - 00:17:00)
Other mistake: When Eddie Sanger is saving Kathleen Riley from "Michael", he gets slashed in the chest, through his leather jacket and sweater. When they meet up the next day, he is wearing the same leather jacket. Although the front is not shown, it is the same type and colour and obviously same jacket. He doesn't seem to be the type who would wear a slashed and likely bloody leather jacket.
Suggested correction: He gets cut through the sweater only. The jacket was unzipped and does not get damaged, therefore the fact that he is wearing it a few days later is a reasonable decision.
Other mistake: When Neal checks his airline ticket it says he departs from N.Y.C. J.F.K. but the movie claims to have him flying out of LaGuardia.
Other mistake: When the man falls out of the high-rise window and lands on the car roof, it never shows him falling through a carport roof. But in subsequent scenes, it shows the car under a hotel-like entrance roof which obviously would have a roof based on the outer pillars. (00:49:00 - 00:51:00)
Other mistake: The film is meant to be set in the US, but there are some odd lines of dialogue that seem to indicate the movie takes place in the England, such as a reference to the (very British) Julia being on her "home turf." This is the result of a change made in post-production, where producers decided to change the setting to the US to make it more marketable to American audiences. Unfortunately, there were some lines about the original English setting that (evidently) couldn't be cut around.
Other mistake: When Jack (Martin Short) is injected with the syringe, it's done in his butt cheek, through his pants, just below the waist of his coat. We then see later Margaret looking at photos taken during the scene, one of them shows the syringe injected through Jack's coat into his thigh/butt cheek area.
Other mistake: When Christopher is in the bathroom stupidly "dabbing" Cathy's back as she's taking a bath there is a glass block window behind them. The window makes no sense. It doesn't match the era or architecture of the bathroom or the home, first of all, but probably more importantly - what's behind it? Where is the light coming from? It's just this random, standing glass block window with an equally-random light source. (00:34:53 - 00:56:49)