Errors made by characters (possibly deliberate errors by the filmmakers): When Harper is first talking to Mrs. Sampson, she obviously moves her legs under the towel that is over her. She is supposed to be paralyzed and wheelchair bound because of a riding accident.
Continuity: When Allen Taggert tosses out the ransom money from Albert Graves' car, the rear projection screen is a city street with other cars on the street. When Harper watches Eddie Rossiter and Betty Fraley drive in and/or out of the money pickup area, it is a dirt road between some oil derricks.