Continuity mistake: At the beginning of the film, when Johnny is first climbing the stairway to his apartment, he climbs a flight, then there is a dissolve to imply that it's a very long stairway, and he's shown climbing another flight. You can see the ground floor only one flight below after the dissolve.
Young Johnny: Dr. Magnus, how's my mother?
Dr. Magnus: It's her pancreas again, Johnny. She's gonna need an operation immediately.
Young Johnny: How much is it gonna cost?
Dr. Magnus: $49.95.
Young Johnny: $49.95?
Dr. Magnus: This week only.
Young Johnny: Where am I gonna get that kind of money?
Dr. Magnus: Why don't you knock over a gas station?