When Vicki smacks Canetto in the face with a hairbrush, he grabs his face in pain, but there are no marks left behind. When he walks outside the door, his lip suddenly is bleeding profusely where it hadn't been a second ago.
Near the end, the police have Rico's hideout surrounded and are spraying it with machine guns. Rico grabs a bottle of acid to throw over Vickie's face but fumbles it, and it goes over his own face. Screaming in agony, he blindly falls through a window. A closeup of him lying on the pavement shows a streak of blood in his forehead but no acid burns.
At the celebration for Frankie Gasto, the rear projection footage of the elevated trains going by, as seen through the large windows, was shot in black and white instead of color.
When Rico is pouring acid on the crepe decoration, smoke appears to be rising from it, supposedly caused by the acid. However, the smoke actually is coming from the opposite (dry) side of where he's pouring, and the liquid actually reduces the smoke.
When the two men are gunned down running after the train, the submachine gun in the foreground clearly is not pointed at the pair.
In the car after the visit to the doctor's office, traffic seen through the car's rear window is a 1955 Chevrolet.
During the trial, there is a woman on the jury. The movie is set in the early 1930s, but the bill giving women the right to sit on juries in Illinois did not become effective until July 1, 1939 after Gov. Henry Horner signed it.
Although the film is set in the early 1930s, the hairstyles, fashions, interior decoration, and choreography are in the style of the 1950s.
At one point Rico (Lee J. Cobb) calls Vicki (Cyd Charisse) a "chick", a slang term not used until the 1940s. At that time, the proper term for a gangster's gal or love interest would have been a moll.
Although the film is set in the early 1930s, the console phonograph/radio in Tommy Farrell's (Robert Taylor) apartment clearly is of a type that was not manufactured until the early 1940s.
When Tommy Farrell is in court defending Louis Canetto, he speaks to the jury and repeatedly addresses them as "Gentlemen", even though he is standing right in front of a female juror.