At the beginning, when Arthur Hamilton is on the train, he gets his newspaper and starts doing crosswords with a pen in his right hand. Later on he signs the contract at the clinic with his holding the pen in his left hand.
When Tony is on the airplane on his way to Malibu he is offered a pillow which he places behind his head. The pillow then disappears and reappears in the next few seconds.
Davalo's hand on the tape recorder disappears between shots.
When Tony is being shown the blackmail film that is calculated to get him to cooperate, the blackmailer sits in the guest chair next to Tony. After an assistance enters the room, the blackmailer rises to greet him, then returns to the chair to find Tony's hat has mysteriously appeared on the chair, and has to be removed for him to sit down again.
During the grape crushing scene, Tony Wilson's girlfriend, Nora, starts to strip-off. Her dress is unzipped down the back. The next shot it is clearly zipped to the top and then unzipped again in the next shot.
Overlooking the extreme unlikelihood of someone being ordained as a Catholic priest, a Protestant minister, and a Jewish rabbi, a Protestant funeral service would not contain passages in Latin.
The number on the note Hamilton is given is 34 Lafayette Street. However, the actual establishment he goes to is marked "125" on the door.
On the train, Hamilton begins to work crossword puzzle that appears in the first section of a major metropolitan newspaper. No newspaper of any stature runs puzzles in the first section.
When Tony is on the airplane on his way to Malibu the "clouds" outside the window move from right to left as you would expect. However they then reverse and move the other way.
When Tony is turned round to face the mirrors after having his bandages removed, part of the camera becomes visible in the middle one.
Cameraman briefly visible during the grape stomping scene.
Early in the film, when the man with the note follows Arthur through the railway station, the shadow of the following camera can be seen clearly on the man's back.
When Tony Wilson first sees his new home, a shadow of the camera/other equipment is visible on the wall as it pans to follow him leaving the studio.
In the final scene, a cranial drill would leave a suspicious hole in his scalp and cranium that would not be destroyed in the planned "car accident".
Mr. Wilson is told, at the beginning, "Take the elevator on your left," but not which floor. The elevator shows several floor buttons.
The shadow of the boom can be seen in the upper right hand corner of the screen just before The Old Man gets up from the couch to move toward John Randolph.
At 1:47:09 Nora undresses to jump into the wine vat. As her dress comes off she is topless beneath it, but as she enters the vat it is clear she has on underwear, unlike the others in the vat. Shortly afterwards, she jumps upwards and again is shown wearing underwear.
At one point Hamilton/Wilson claims he was next in line for bank presidency. Highly unlikely in view of the fact that during early scenes he didn't even have a private office.