Continuity: The length of Edward G. Robinson's necktie rises and falls, often within the same scene.
Great sites
Mistakes
During the whole scene with the policeman waking up and confronting Rocko, there are several wide-angle shots of the room. The windows show fairly bright light coming from outside...it must have been a case of clear-day thunder and lightning, I guess. See more...
Key Largo mistakes
Continuity: When Lauren Bacall attacks Edward G. Robinson (after he goads her wheelchair-bound father-in-law into attacking him, causing him to fall over), she clearly scratches him on his left cheek. Shortly afterwards, Claire Trevor notices the scratch marks and wonders what happened. The only trouble is, she notices them on his right cheek.
Visible crew/equipment: During the storm scene, there are two shots of the hotel from outside along the beach. In both instances, the wires holding the palm trees are visible.