Blooper

Wynant removes his eyeglasses when he realizes the bonds are missing from the lockbox, and he turns to Tanner. As he steps towards Tanner, however, he is wearing his glasses and removes them as he speaks.

Nick walks into a bedroom with a bucket full of ice. Minutes later, he walks out of the bedroom, but the ice has melted.

The same shot of Asta pushing the kitchen door open, only to turn around and head back into the kitchen during the party, is used twice.

Nick has a drink in his left hand as he and MacCaulay talk in the living room. There then is a shot from behind Nick, and his left hand is propped-up against his head with his left arm on the back of his chair.

After Nora gets dragged by Asta to find Nick, Nick is explaining to the bar manager that Asta is a well-trained dog. Initially, Nick has Asta's leash in his right hand and points at Asta with his left, but when they focus on Asta, Nick is pointing with his right hand and holding Asta's leash in his left.

Christmas Eve, when Dorothy Wynant meets Nick in a bar, she says her father disappeared 3 months earlier. At the opening of the movie, which depicts the day in New York that her father disappeared, it is snowing. Late September is too early for New York City snowfall.

When Mimi Jorgenson dials the operator, she requests to be connected to Miss Wolf's residence and then gives the address; the operator connects her almost instantly without waiting. This is unrealistic, especially in that time period. Even in a hotel, it would take an operator much longer to look up the person and then connect them.

When Mimi goes to Miss Wolf's building, she asks for Wolf's apartment number. The concierge gives her number then asks who is calling. Mimi does not give her name and says that Miss Wolf is expecting her. In reality, a concierge will not give the apartment number out to anyone especially a stranger unless the tenant has given permission for the person to come up.

Gilbert accuses Dorothy of having an Oedipus complex. An Oedipus complex is antagonism to a father on the part of a son. What Gilbert meant is that Dorothy had an Electra complex, antagonism to a mother on the part of a daughter. The term "Oedipus complex" can apply to a child of either gender who is antagonistic towards the same-sex parent (i.e., it is not male-exclusive), so Gilbert didn't make a mistake.

When Nick and the coroner look at the body through the Fluoroscope, the bullet, and a piece of shrapnel, appear as bright white. The Fluoroscope uses X-rays except it is viewed on a screen instead of film. Dense objects, such as bones, appear dark, as it appears in the movie. The bullet and shrapnel should then be even darker as it blocks even more of the X-rays. However, this would not have shown up well in the movies, so they were made bright white so the viewers could see them easily.

When the police arrive at the Wynant's lab, the abnormally fast movement of the cars and the police indicate that the film has been speeded up.

When Stutsy first approaches Morelli at the bar, Morelli mouths the words, "Hiya, Stutsy", but no audio is heard.

(at around 1h) There is a small round mirror on the facing wall. Zooming in, the director can be seen seated in shirtsleeves with a dark tie.

During the Christmas party Nick greets Face and invites him in saying "Shed your chapeau". Face had already removed his hat, as gentlemen do, when entering the apartment.

"Asta" is a female name, and in Dashiell Hammett's novel Asta is not only female, she's a standard schnauzer rather than a wire-haired fox terrier. Possibly trained schnauzers, standard or miniature, were in short supply.