Continuity: Near the beginning of the film as Harry enters Cini's apartment we hear a gun being cocked and then see a .45 pistol being pointed at Harry's head. You can clearly see the hammer is not in the cocked position.
Crew or equipment visible: When Harry Mitchell walks into the adult theater, you not only see the reflection of the camera man, but you also see the reflection of the boom mic in the open glass doors for a moment.
Continuity: When Mitch is taken to a secret location to meet with the extortionists, he sits in a wooden chair against a "wall". He sees his mistress shot five times. After the bad guys leave, he jumps up when he realizes he is in the chair she was murdered in. But, when he first walks in, there is no blood on the chair or wall behind him.
Continuity: When Doreen strips for Harry she gets down to just panties, then in later reverse angle shots she her garter reappears.
Factual errors: In the final scene when Alan starts the E-type Jaguar he does it by turning the key, yet that car (as to all pre-1968 XKEs) starts with a starter button on the dashboard, as was demonstrated when it first appears in Harry Mitchell's garage.
Revealing mistakes: The "exploding" Jaguar is slightly different than the one used throughout the film. It has a dent between the door and bonnet, lacks the passenger-side rear-view mirror, and the hard top is missing the glass rear window. Given the value of the car it is forgivable that the "real" one was not blown up.