Continuity mistake: Marlowe sits in front of Joe Brody's apartment building, The Randall Arms. Later as he follows the gunman that shot Brody we see it from inside the car and the registration stickers are different. (00:47:40 - 00:57:20)
Continuity mistake: When Frank, the DA and the policeman are discussing the accident, the policeman notices the electrocuted cat and it is shown next to the ladder. In the subsequent wide shot the cat is lying between the beams of the ladder. (00:42:50 - 00:43:35)
Continuity mistake: Watch Devlin's hands in the cafe in Rio. They open and close between shots.
Continuity mistake: The postman hangs his bag to the hook on the wall. By the noise, he knows a split-second in advance that an explosion is about to happen, and ducks. The actor ducks out of view; we are not supposed to notice that once he disappears, film editing inserts the part when the background partially detonates. We however do, because the bag in the foreground changes position in the space of a single frame. (00:05:25)
Continuity mistake: The Cadillac limo changes models at times, also having blackwall or whitewall tires.