In the film's opening decapitation, blood spatters across the car before the decapitation even happens.
The girls escape their room early in the day, but when Ike and Addley are interrupted to go rescue Mother from Queenie, it is almost night, as evident by the low light. Then it shows the girls escaping into the woods and it is earlier in the day again, as there is much more light.
At the beginning of the film, when the couple are attacked in Mother's car, there is blood on the woman's clothes before the man is attacked.
When the girls are kidnapped and put in the sleeping bags, they are wearing night clothes as they were in bed. When the sleeping bags are re-opened in the house, however, they are now fully clothed (with one even wearing jewelry) with no explanation as to how this happened.
Trina's gag changes positions as she watches through the window. Additionally, the stuffing in her mouth disappears altogether.
Abbey chokes one of the two sons to death, but the crumpled-up cloth that she is choking him with does not cover his nose. He could easily breathe through the nose and still survive.
In the beginning of the film when the couple are in Mother's car, the man is obviously a dummy.
The TV that Abbey drops on Ike's head in the film is obviously empty and has no working parts in it.
Mother is still breathing after being choked to death.
Abbey's cuts on her hands are too big, clearly revealing that fake skin was used for the wounds.
When one of the two sons starts hitting the girl on the car at the start of the film, it is obvious that he is missing her.
In the stadium flashback scene,Brad Dobson takes his socks off while waiting for Jackie but in the next shot his socks are back on.
It is seen that Jackie lives in New York at the beginning of the film; however, her car has New Jersey license plates. if she really were a New York resident, of course, her car would have New York license plates.
The city scene in the film opens with a caption that says "Chicago", yet a doorman says that it is New York.
Trina's address on the telegram is 210 Alameda Road, Beverly Hills, CA, 94510. Alameda is one of the main streets in downtown L.A., but there is no Alameda in Beverly Hills, Road or otherwise, and the zip cope 94510 is in Solano County, which is north of San Francisco.
The blonde girl is lowered out of the window in a sleeping bag by her friend, yet comes back upstairs straight after to free her friend, and does not even have to unlock the door. If the door was unlocked, she could have just walked out rather than going out of the window.
(at about 36:00 into the film) When the old man is talking to the girl whose mammoth left breast takes up the right side of the screen, the boom mic dips into the top of the frame.