Continuity mistake: In the scene where Bill is cutting up the pig and is about to show Amsterdam the "kill" spots, he wraps up a piece of the pig for an old woman standing nearby. He throws the meat to Amsterdam to give to her and then reaches to unsheath a knife strapped to his right side. After Amsterdam gives the woman the meat and turns back around the shot cuts back to Bill and he is seen unsheathing the same knife he was holding seconds before.
Continuity mistake: During the theater scene a man tries to murder Bill the Butcher but Amsterdam saves his life. As Amsterdam is wrestling with the culprit his hat falls off but in the next shot it's back on, then off again.
Continuity mistake: When Jenny tells Amsterdam that she's leaving for California, she is seen walking through a stone walkway. The camera angle changes and she is seen just turning around a corner and the walkway is nowhere to be seen.
Continuity mistake: The moment when Bill attacks Vallon is very badly edited. There's a shot of Bill raising his cleaver, and it must be at Vallon because he had his eyes fixed on him already for a while. Then you see Vallon's arm crushed by a halberd, then again Bill staring at Vallon, then Vallon turning around, unharmed as it seems, and finally Bill slashing Vallon with his cleaver. (00:09:55)
Continuity mistake: When Amsterdam meets Jenny for the second time he is seen stealing what looks like an apple and is in his right hand. When she runs away he doesn't have the apple, but when the when the shot is on Amsterdam the apple reappears for him to throw it to the ground. (00:45:30)
Revealing mistake: In the beginning of the Five Points battle it happens very often that people get hit badly with a sharp weapon but don't receive any wound. Watch for example in slow-motion how Bill sets out to mow down victim after victim with his cleaver. Later into the fight it becomes a lot bloodier, and sometimes the blood seems to come out of the weapon (e.g Monk's club seems to have a generous blood reservoir). (00:08:15)
Revealing mistake: In the last scene where Amsterdam is crossing the black man's arms, wait until the camera pans onto Jenny. In the background there is another dead man and you can see him breathing pretty heavily. (02:29:30)
Continuity mistake: When Jenny rubs her fingers over the old scars on Amsterdam's chest, you can see light under the tips of the scars as if they peeled up. (01:05:50)
Continuity mistake: When Amsterdam and Jenny continue talking after Bill has just left them in the bedroom, Jenny's hands keep shifting from both hands on her chest to just one hand between shots. (01:28:45)
Continuity mistake: Jenny pokes Amsterdam with her knife on the right side of the neck as he is trying to retrieve his medallion from her. Shortly afterwards, while walking back with her, he is seen dabbing the left side of his neck in two different shots, one of them pretty lengthy. (00:50:00)
Continuity mistake: When Amsterdam tries to kill the butcher and fails, the butcher straddles Amsterdam on a table and tosses a cleaver in the air. The cleaver rotates counter-clockwise so that the blade is rotating backward; however, when the cleaver lands, it is rotating clockwise so that the blade sticks into the wooden table. This would be impossible the way the cleaver is tossed into the air with a back-handed flip. (01:42:15)
Suggested correction: It is possible, if it falls quick enough. Doesn't matter where it rotates, if it is blade down at the moment of touching the table - it will stick.
Continuity mistake: At the end of the fight in the bar between Amsterdam and Bill's Irish henchman, Amsterdam is in four consecutive shots from two angles bent over in pain, leaning back, doubled over again, and leaning back again as Bill approaches him.
Factual error: The prayer uttered at the beginning of the movie ("Saint Michael, the Archangel, defend us in battle; be our protection against the wickedness and snares of the devil") was composed by Pope Leo XIII in the year 1884. The movie is set during the American Civil War in the 1860's.
Continuity mistake: The scene during the riot where Bill and Amsterdam are fighting in the smoke, Bill takes what looks like shrapnel to the side of his stomach, but when Bill and Amsterdam face off (standing on their knees) just before Amsterdam stabs Bill, you can see Bill's vest has no cuts or blood from the shrapnel he just pulled out of his gut (and it looks like he is wearing a new vest).
Revealing mistake: In the scene when Bill confronted Monk outside the barber shop, Monk invites Bill in to settle their score the democratic way. As Monk led the way, Bill threw his big butcher knife into Monk's back. The knife can be seen bouncing off Monk's back onto the ground. (02:19:05)
Factual error: The Snooker scene appears incorrect, since the earliest form of Snooker was invented in India circa 1875 - by British soldiers. At any rate, the blue ball shown in the movie was not added to the game until even later. (02:15:00)
Revealing mistake: In the Five Points battle scene, in the beginning of the movie, look at Bill the Butcher's blades when he walks through the crowd towards Priest Vallon. There is no sign of blood on them, even after he stabs a lot of people.
Continuity mistake: During the funeral, when they are transporting the coffin in the street, there's a dog besides Bill the Butcher. He keeps changing place.
Continuity mistake: The scene where Amsterdam is climbing on the Portuguese ship, we see that there are still four people left in the small boat and we see that Johnny is the first one on the ship, so how did the rest of the gang board the ship before Johnny and Amsterdam? They even know that the ship has been ransacked. (00:39:05)
Suggested correction: There was no scene that shows Johnny was first one on the ship. There was a scene where he climbs before Amsterdam who was the last on the ladder, and all the gang at that moment was already onboard, because they climbed there offscreen.
Other mistake: In the sequence where the "Natives" celebrate the 16th Anniversary of their victory over the "Dead Rabbits," we can see that the year is 1863 while the battle shown in the beginning of the movie happens in 1846. Shouldn't they have been celebrating 17th anniversary instead of a 16th?
