After going on break, he turns both wrenches in the same direction. Before that he appears to be tightening them in opposite directions.
(at around 33 mins) During the visit of the Minister in jail, Charlie sits next to the Minister's wife and they make funny noises. The distance between them varies between shots.
(at around 17 mins) After Charlie goes crazy, he comes back with an oil can and sprays Big Bill in the face with the oil. We then catch a quick glimpse of Big Bill's back which is already stained black, but in the following long shot, his tank top back is pristine white in color.
(at around 1h) During the scene with the press at the factory machine shop, Chaplin leaves his boss's coat under the press, flattening his pocket watch. A trap door under the press is clearly visible as a stagehand accidentally leaves a corner of the coat caught in it, and Chaplin must yank on the coat twice to free it.
(at around 46 mins) When Charlie goes to let the gamin into the department store, the escalators are off, allowing him to rush down the stairs going up. However, when he goes back downstairs and notices the burglars, the escalator is working, allowing him to do his stunts.
(at around 4 mins) When the wrench gets stuck on the bolt, Chaplin loses hold of it, but he has it in his hand when the foreman comes by.
After a brick hits the police officer all the officers go over to the tramp. The gate he is in front of is open at first with a wheelbarrow in the gate opening. This position of the gate and wheelbarrow occur for two or so scenes. In the last scene the gate is suddenly closed and the wheelbarrow has been moved to outside of the gate.
(at around 14 mins) When Chaplin falls from the conveyor belt into the machinery, you can see that he drops at least one of the wrenches but then has both when he tightens the nuts on the large gear.
(at around 15 mins) When Charlie comes back out of the machine, the footage is played backwards. The men hammering in the background give this away.
(at around 17 mins) In the factory, when Charlie messes with the big machine, he pulls some levers out. Shortly after, he squirts oil on the other factory worker, and the levers are still out. Inbetween these shots, is a short clip where the levers are back in their original position.
(at around 1h 17 mins) During the Singing Waiters musical number, the singers' lips do not match the soundtrack.
(at around 1h 14 mins) When Charlie tries to get the roasted duck dinner to the table, the items on his tray are fixed in place. The wine cradle barely moves when he swings the tray overhead, yet when the tray is on the table seconds later, it does.
(at around 1h 3 mins) When the factory worker is trapped in the machine, the position of some of the wheels changes between shots.
(at around 6 mins) The Bellows Feeding Machine moves closer to the boss's desk between shots.
(at around 18 mins) When Chaplin grabs the passing chain to flee from his workmates, the next shot shows him actually sitting in the chain with the straps of his overalls undone and hanging free. Prior to this and when he is back on the ground the straps of his overalls are done up.
(at around 18 mins) Set lights clearly reflected in car window as the Tramp leaves the factory in the ambulance.
(at around 10 mins) When Charlie is in the Feeding Machine, a wire can be seen from the left, moving the rotating corn device.
(at around 14 mins) One of the men on the moving line with Charlie, is operating a press/drill. When he moves it down towards the plates with the two nuts, it never actually touches the plates.
(at around 1h 11 mins) The juvenile authorities have a photograph of the Gamin included in their warrant, even though they never had the opportunity to take her picture, and there's no evidence of photographs in the humble home of the Gamin's family.
(at around 19 mins) The wire holding the flag on the back of the truck is clearly visible.
(at around 57 mins) Charlie attempts to go swimming and hangs his bathing suit out to dry. It disappears a few minutes later when he leaves for the factory.
(at around 36 mins) When Chaplin accidentally launches the ship, his position in relation to the moving ship changes between shots - he launches the ship from the side but when is looks at it descending into the water he is directly in front of the ship.
(at around 1h 25 mins) In the final scene of the film, when the tramp and the gamin are walking towards the camera, the sun is behind them (as seen by their shadows). When the camera angle switches, the sun is now in front of them.
(at around 52 mins) After Charlie has been doused with rum, his suit is soaked. When Big Bill recognizes him directly afterwards, his suit is mostly dry.
(at around 26 mins) When the inmates are eating, the bread that Chaplin and his cell mate fight over, disappears after they get up.
(at around 59 mins) After Chaplin rushes through the crowd with unemployed workers, and enters through the gate, one of the men on the inside seems to be locking the gate, however the gate opens slightly when he walks away.
Two plates of food on The Bellows Feeding Machine change, after two hex nuts are unscrewed from one part of the machine.
The Tramp gets his mouth stuffed of the hex nuts unscrewed from The Bellows Feeding Machine. By the next shot, when the mouth wiper is malfunctioning and hitting the Tramp in the face - the hex nuts are no longer shown stuffed in the Tramp's mouth.