Continuity mistake: During the scene of the fight between Dillinger, and Melvin Purvis and the Little Bohemia Lodge, it shows Purvis shooting from the side and he has a straight magazine in his Thompson, but when the shot faces him he has a drum magazine in his Thompson, but when it goes back to his side to reload, he again has the straight magazine.
Continuity mistake: When they break out of the Indiana jail they leave in the sheriff's own vehicle. The vehicle has no markings on the driver side door. When they arrive at the traffic light and the scene is panned you can see Police written on the drivers side door. Then they zoom in on the traffic light and above and to the right of the light in the window glass you can see the reflection of numerous vehicle driving by on an empty street. Then its back to the marked vehicle with an officer in the rear seat wearing a police hat. Then its back to the original unmarked vehicle as they drive away.