Gaffes

(at around 12 mins) When the paper airplane is made it is snub nosed (there is no point on the front), whereas when it is thrown from the tower it has a pointed nose.

(at around 1h 1 min) When Marion leaves Arnold's apartment and runs onto the street to vomit it is raining heavily, however when she arrives back home her hair and clothes are completely dry.

(at around 1h) The purse strap changes positions between shots when Marion heads to and enters the elevator.

When the characters take Heroin, either injected or snorted, the sequence showing their eyes dilating is inaccurate. Opiates produce a constricting of the pupil. However, the dilating is correct when the characters are using Ecstasy and Cocaine.

(at around 1h 30 mins) When surgeons amputate a limb, they first remove the muscles/tendons and the nerves, and then they cut through the bone. They do not simply saw through the flesh as depicted here.

(at around 1h 30 mins) During electroconvulsive therapy (ECT,) the character is shown as being conscious and suffering greatly, when in reality the procedure is done under anesthesia. The patient is not conscious, nor do they experience discomfort.

When Harry arrives at the hospital for his arm, he is released to the police with no apparent medical treatment given him until after he is checked in to the prison. Any doctor who discharged him from the hospital with his untreated arm in such a severe state would surely have lost his medical license.

This is an attempt to incorporate the mood of the novel written in 1978, when deep south medical facilities were inadequate, often abusive and uncaring of their patients. Drug addled northern drug addicts who are recuperating at a prison work farm are not likely to bring an accusation against that doctor.

(at around 1h 27 mins) When Harry calls Marion from the hospital she picks the phone up with her right hand and puts it on her left ear but when the camera focuses on her it's on her right ear. This is almost certainly a mirror shot, not a mistake.

(at around 12 mins) When Sara is trying on the red dress but it won't zip up all the way, in the mirror behind her you can see the 'fat suit' used to give Ellen Burstyn the larger appearance.

Whenever someone takes drugs and their pupils "dilate" you can see that it's a normal eye being distorted by a computer because the arc of reflected light also is distorted.

(at around 1h 1 min) When Marion is leaving Arnold's flat for the first time you can see some parts of the steady cam outlined under her coat. When she catches some wind while leaving the building, the coat is lifted up for some instants and you can actually see them.

(at around 55 mins) When Marion stabs Arnold in the hand with a fork, you can see fork marks on the fake hand from rehearsal.

There are no "fork marks on the fake hand" because the hand wasn't fake - the fork in the hand and the blood were the fakes.

(at around 1h 35 mins) When the two ladies visit Sara and are outside sitting on a bench, you can see at the right lower part of the bench the cotton trying to appear as snow.

Since Director Aronofsky has an in-house digital effects company "Amoeba Proteus" for just such things, it's unlikely they used cotton for snow.

(at around 1h 4 mins) When Harry and Tyrone are leaving New York for Florida, Tyrone pricks Harry to the right arm. You can see pain in Harry's face. But as we know Harry's wounded in his left arm.

Tyrone didn't "prick" Harry's arm. He punched it. Wounded isn't necessary for a punch to cause pain.

(at around 58 mins) Marion's bangs when she is at dinner with Arnold near the end of the movie constantly change from being behind her ears to down in her face.

Her hair did not move any differently from how it would normally while she turned or nodded her head. Not "constantly changing" from behind her ears to over her face.

(at around 1h 10 mins) Sara is in her apartment wearing her red dress, creeping around trying to avoid her refrigerator, popping her pills and watching herself appear all dressed up on Tappy's show. There is a pot on the stove and her vacuum cleaner in front of the stove. At different cuts in the same scenes, the stove is alternately clean or has pots and items on it, and the vacuum cleaner is there or missing, or changes position. These changes occur because Sara is hallucinating.