(at around 39 mins) During her rant in a jail cell, Mother Firefly is seen holding her hands far apart for emphasis when her hands are supposed to be handcuffed with only about a foot of chain.
(at around 6 mins) When storming the Firefly house, Sheriff Wydell is loading a Remington 1100 shotgun (a semiautomatic), but when he is shown from behind firing upon the house he is clearly using a Remington 870 (a pump action shotgun).
(at around 19 mins) When Candy is talking to her boss, he puts the money in the box and it changes position, and then even disappears in one shot.
(at around 1h 30 mins) When Baby is in Charlie's car toward the end of the movie, Wydell uses his ax to smash the windshield to pieces. It is back whole once they leave the house, even showing bullet holes at the end.
(at around 21 mins) When Otis and Baby are driving to the motel, on the dashboard there is a closed box of cigarettes, yet in the next shot they are open.
Two of the officers storming the house at the beginning of the movie are firing M-16's, which fire a .223. The armor the Fireflies wore would likely not have provided sufficient protection at the ranges the officers fired from.
(at around 12 mins) The license plate from the vehicle that is stolen from the maid by Baby and Otis is an all numbers license plate. This type of license plate is only used by government vehicles. Civilian vehicles would have both numbers and letters.
In the beginning, when clippings of the killings are being shown, one sentence reads, "police have rules out the idea of suicide." This has two errors: 1) Since this is the beginning of the sentence (first sentence in the paragraph), "police" should have a capital "P;" 2) "rules" should be in preterit tense, "ruled."
(at around 1h 19 mins) During Sheriff Wydell's meeting with Rondo and Billy Ray at Billy Ray's trailer. As Sheriff Wydell walks away, Rondo is seen wearing a baggy style of pants that did not exist in the late 1970s.
(at around 3 mins) The open credits say that the raid was done 1978, the k5 blazer that pulls up in front of the farmhouse has the headlight setup of a 81-87 Chevy truck.
When Otis is sitting in the chair in the motel, his dialogue is out of synch with his mouth.
(at around 1h 14 mins) When Sheriff Wydell stops Charlie and his sidekick in the road after they buy the chickens, Charlie gets out of his car and you can see microphone equipment sticking out from underneath his vest.