Mickey shaves his head right before the interview, but as he is led to the interview room there is a shot of his neck with chains on it, and you can see his hair.
When Scagnetti is with the prostitute, as he starts to choke her and they roll off the bed, he is seen wearing a thong with just a string in back. When he gets up and is seen standing by the window, his underwear has changed into briefs.
When Scagnetti is in the room with the prostitute, her bra keeps disappearing and re-appearing ("Director's Cut").
Blood from a previous take is visible on the wall before the blood splatters on it when the cook is shot.
When the warden has been locked in the prison and the prisoners are charging at him, the shot facing the guards when they open fire on the prisoners clearly shows the warden climbing the bars, then cuts to a reaction shot of the warden still stood normally on the floor, then shows another shot of him climbing the bars.
Mace does not mist, like hairspray. It shoots in a stream, to deliver a maximum dose in a targeted area.
No-one would be physically or mentally capable of casually walking around a shop after being bitten by a rattlesnake. However, as director Oliver Stone points out on his DVD commentary track, the snakebites are not supposed to be taken literally, but as a metaphoric infusion of 'knowledge' from the Indian shaman. He acknowledges that in reality, they should be dead, but he argues that the film is not a realistic depiction of reality.
Leading up to the Super Bowl the number of victims that Mickey and Mallory murder change several times from fifty six to fifty seven to forty eight and other numbers in the deleted scenes and unrated cut. This might have been done deliberately by the film makers to give the killers the larger than life pop lore they wanted.
During the Prison Riot all the doors seem to be magically opened, the reason supposedly that the doors are jammed. The security locks in prisons are tested several times a day, and at the beginning of a riot all the doors would close and lock. However, as with the issue of the snake bites, this comes from an overly literal interpretation of the film, something which Oliver Stone strongly discourages on his DVD commentary track. The riot is not meant to be taken as a realistic depiction of an actual prison riot, and Stone acknowledges that great liberties were taken in the scene with the full knowledge that they weren't realistically accurate.
No human can take such a repeated and concentrated dose of Mace as Mallory does and open their eyes so soon afterward, not to mention Mallory's eyes open quite easily and do not shut during the spray. Mallory also doesn't apply any water to her eyes, and seems to recover naturally only minutes later. This is one of many scenes which are supposed to be stylized and unrealistic.
During the prison riots, guards can be seen firing from a security tower with their shotguns, only to have several prisoners overrun the tower. This makes little sense as all guard towers have doors with locks on the inside. Again however, this is coming from reading the film in too factual a manner. The riot is not supposed to be a realistic depiction of such an event.
When Owen is leading the group through the passage in the prison, the barrel of the gun in his left hand is not a barrel at all, but a solid rod as it has no hole in it.
During the wedding scene, as Mickey takes Mallory's hand to cut it, her palm is already red from having blood on it in previous takes.
When Mallory attacks Scagnetti in her cell and the guards rush to unlock it, you can clearly see it is at the end of a hallway (one guard pushes the other one out of the way as they both scramble to unlock it. But when Mickey reaches Mallory's 'cell' to rescue her, he enters two doors before where hers would be.
When Kavanaugh gets up on his knees after Mickey takes control of the interview, one can easily make out the knee pads he is wearing underneath the uniform.
When Mickey and Mallory are in the drug store and Mickey sees the Wayne Gale Expose on them on the TV, and realizes that the Drug Store Clerk has hit the panic button he fires 2 shots at him behind the glass window but the glass window doesn't shatter. This is because they are using blanks on set but in reality it doesn't make sense because it would shatter.
Mallory plays a 45 on the jukebox....The Way I Walk by JACK SCOTT but the record played is ROBERT GORDONs version.
The interview at the prison takes place after the conclusion of the super bowl broadcast, which could be no earlier than around 6:30 p.m. (pacific time), when night has fallen over the whole country (in late January or early February). However, the interview, prison riot, breakout, and aftermath all occur during full daylight.
Shadows of the camera/cameraman can be seen sporadically during the final sequence.
After the prison escape, Mickey explains that their pursuers gave up after he killed the only hostage they cared about. That the pursuers would want to capture the person or persons who had murdered someone they cared about is ludicrously ignored.
The Indian tells a story about a poisonous snake. Snakes are venomous, not poisonous.