Factual error: Toward the end of the film, Matthew McConnaughey is in his office late at night and hears someone outside (it turns out to be his wife). However, McConnaughey draws a revolver from his desk drawer and we can hear (but not see) him pulling the hammer back to cock the gun. Problem is: When pulling back the hammer on a revolver, the cylinder turns to rotate the next bullet into position. The cylinder did not turn. The sound we heard was obviously added by the sound editors after the scene was shot.
Continuity mistake: At the end of the movie when Sandra Bullock character is in the hospital and the nurse revealed to her that Carl Lee was innocent, look carefully at the TV. You can see Jake, Harry Rex and Lucent standing outside the courthouse, but in the very next scene they haven't even left the courtroom.