When Johnny North is recovering in hospital after his accident, the bandages and the pads underneath change position between shots.
While the gang is going over the heist plot in the garage, Jack stands up and slaps Sheila with his right hand across her left cheek. When she recovers from nearly falling over, she holds her right cheek. In another shot soon after, she is nursing her bruised left cheek.
During the car race, there is an instant when no cars can be seen on the track. There is an edit at that point, because people in the crowd in the background shift position.
Silencers don't work on most revolvers.
Early in the movie, Johnny comes in off the track after a solo test session. There are no other cars on the track, and he has "goggle eyes"; i.e., dirt on his face except where his driving "glasses" were. Drivers only look like that after having been in a race. Since he was on the track by himself, there would be no source of that dirt (from other cars).
The Ford Cobra did not have had a rear control arm; it had a solid rear axle.
Although most of the staff and many of the students in the blind school are sight-impaired, all informational signs, names on doors, and room numbers are painted with no accompanying braille information.
The rear-screen projection used for the go-cart racing scene is poorly done, and the editing from the process shots to the main shots, with the change in color, brightness, and sharpness is jarring. It is the same with the driving during the race, where multiple studio lights can be seen reflected on the car and drivers' helmets.
When North goes to punch Browning, it is obvious that Cassavetes misses Reagan by a good six inches or more.
During the scene in Browning's office, part of the set casts a shadow on the background matte painting.
Near the end, there is a shot of the 3-way intersection by the hotel. There are no yield signs, no stop signs, no crosswalks, and despite the amount of cross traffic, not one vehicle uses indicators. Clearly a studio set with choreographed traffic movements.
The 1959 Ford Fairlane used by the robbers as a police car is black all over whereas a California Highway patrol car would have had white doors.
When Jack and Johnny move the "detour" signs after the mail truck passes by, the arrows on the signs are pointing in opposite directions.
At the start of the race, Johnny presses the accelerator to the floorboard with his right foot. However, his left foot is nowhere near the clutch. In a manual transmission, the clutch would need to be released while simultaneously accelerating.
When North drives his Cobra into pit row prior to the race that Sylvester recalls, in flashback, a Ford badge is clearly visible on the side. In addition, there are several other Cobras in the race, presumably with Ford badges. Later in the film, Strom states that the heist was four years ago (from 1964), and so the race depicted was even earlier than that. Carroll Shelby did not drop the first Ford V-8 and transmission into an AC Cobra until February of 1962, and Ford did not start selling them until later that year.
In the early murder of Johnny North by Storm and Lee, they fire 18 shots collectively but there is no blood spatter, no bullet wounds nor any blood stains produced.
When Charlie and Lee push their way into Sheila's apartment, Lee closes the door once, but the sound of it closing is heard twice between shots.
Towards end of film, camera shadow is visible on Jack Browning's rifle case as he exits his car.
When Charlie and Lee go to Miami to visit Earl Sylvester, there are mountains visible in the background as they drive up to the garage.
There is no reason that the thieves should have to follow and overtake the mail truck, rather than just lying in wait for them down the road.