39 minutes into the movie, Tony is walking down the street and passes a Salvation Army Santa Claus who is ringing a bell by his kettle. On top of the kettle stand is a sign with the Salvation Army crest on it. In the next shot, the sign atop the kettle stand is missing.
When Carol kneels at Anthony's bedside, her hands alternate between being on his body, to being clasped under her chin, and back again between shots.
At 2:04:54, the butler's hand is on the rail, but he is then seen placing his hand on the rail.
At 1:29:12, the way that Tony holds the phone changes.
When the police call Tony, the desk sergeant says he is from the "42nd precinct." The Philadelphia Police Department has districts, not precincts.
When Tony fights the truck driver, he takes a left hook to the jaw. Yet he is cut above the left eye.
While Chester Gwynn announces to Anthony that he had lost his right arm in battle, the outline of his right arm can be seen underneath the blanket as they carry him away.
After the marriage is postponed, while Joan and her father are driving home, Barbara Rush takes her eyes off the road for way too long.
When Tony is trying to talk Carol into going back to her own bedroom as he leaves his bed to hold her, he calls her Joan.
Louis Donetti and others make reference to "Main Line" (i.e., "...on Main Line") without the definite article, which is always used in referring to THE Main Line.
Mike Flanagan is shown as leader of the "South Side Political Club." South Philadelphia is never referred to as "the South side."