When Walter pulls in to park and hits the parking meter, he reverses and parks. The car is visibly outside of the parking lane lines. After the cut, he gets out of the car and the car is within the parking lane lines.
In a close shot of Walter and Rodger where in the Rolls Royce driving the rear view mirror is missing and then when they pulled out to a long shot the rear view mirror was back in place.
If Roger really was Walter's son, as depicted in the film, he would be biracial and not full-blooded African-American.
When Walter and Roger check into a hotel the sign says "Free Ice and TV". Later in the room, Roger wants to watch TV and states that the TV requires payment of a quarter (25 cents) to watch it. This is most likely due to shady business tactics which can promise something but later retrieve that promise with diverse excuses.
When Walter and Roger move into the run-down apartment in Watts, very low flying jets can be heard overhead. The nearest airport in the area would be LAX which is approx. 13 miles due west. LAX is too far away for such low flying aircraft.
Walter is fired and left destitute with few options for income after the discovery of his black son Roger. However, the film overlooks the gross violation of Walter's civil rights regarding his termination, which Walter could easily use as a threat to get his job back or to sue his former boss for substantial money.