Continuity mistake: In the Police Station at the beginning of the film James Dean takes off his flecked jacket to reveal his spectacle case in his top pocket. As his character does not wear glasses the offending case is removed in the next scene.
Continuity mistake: In the scene when Plato is laying on the ground outside of the observatory, he is only wearing one shoe. This is stated in the movie. The foot with the shoe on keeps alternating between shots. At first his shoe is only on his left foot. In the next shot, his left foot is clad only in socks.
Continuity mistake: When James Dean reaches into his car to switch off the radio, he reaches in with one hand, but when the camera focuses in on the radio being switched off, it's his other hand that's switching it off.