When Eva is calling on the pay phone at the club after she sees Butcher, a coin purse alternately appears and disappears being clenched in her teeth.
When Butcher is walking around his hair is combed, parted and neat but in a close-up of his face his hair is very messy.
As Eva reaches her dresser when she returns to her dressing room the radio begins to play by itself, abruptly (it was not on when she left).
When "Butcher" is standing on the giant electrical crane, all the closeups of him show him moving a lot, but when they cut to the long shots, he is just a dark silhouette with no movement whatsoever.
When Benton enters Eva's dressing room, her hand is on her head. Cut to a close-up, and it's now at her side.
The guy with the flamethrower is wearing an arc welding helmet, totally unnecessary for the job at hand and completely hilarious on its face.
For every time Butcher Benton is shot, there are never any bullet holes in his jacket.
When Benton steals Carney's car, he simply shifts into Drive and goes off. The engine hadn't been running, nor does he put the key in the ignition and start it.
On two separate occasions only minutes apart, Butcher Benton is shot multiple times from point-blank range, specifically a distance of only a few feet. During both shootings he is wearing the same light-colored jacket, but no bullet holes or powder residue is ever seen on the jacket.
When Squeamy is trapped in the elevator, his pistol is heard to discharge a couple of times when he is clearly not shooting.
The Butcher is driving from San Francisco to Los Angeles. Just after the roadblock, a sign indicates that he is 22 miles from Merced. Merced is nowhere near the route from San Francisco to Los Angeles.
Early on, crooked lawyer Paul Lowe finds the map showing where the $600,000 in stolen money is hidden, yet makes no attempt to recover it.
In one scene Lt John Lauder addresses Lt "Dick" Chasen as "Mike".
At one point a character refers to Butcher Benton as a "monster-made man," which seems the wrong way around.
Eva Martin is supposed to be a stripper, but when the detective interviews her when she has just gotten off the stage, she is fully clothed.
Professor Bradshaw order his assistant to bring a syringe, pronouncing it SEER-ringe, but just a few minutes later, asks for another, pronouncing it correctly as serr-RINGE.