Continuity mistake: When Ray and Alex incapacitate the last of the 4 cops, he flips on the ground wearing his hat. When they approach him to finish him off, his hat is at distance. (00:10:00)
Other mistake: Throughout the whole scene when Black Caesar is wounded by the Irish hitman several passers-by can be seen looking directly into the camera, and in many shots people are crowded together on the sidewalk watching the filming. Conversely, the hitman fires a big and loud revolver in the middle of a crossing with dozens of people and cars in close quarters, and nobody bats an eyelid. (00:03:00)