Continuity mistake: When Cousin Avi, Tony, and the big henchman are driving after bagging Boris, the big henchman is playing with a knife while they talk about killing Boris. The next time we see the henchman he is holding a sabre of sorts across his torso. After they crash, the sabre is going directly into his chest. This would not have happened unless at some point he held the sabre with the tip directly towards him.
Continuity mistake: Before Boris shoots Frankie Four Fingers, he reaches for his gun, then from the different angle he is still fiddling with his earplugs, not having yet reached for the gun. Then back to the original camera angle where the gun is in Boris' hand ready to shoot.
Continuity mistake: At the campsite when Mickey's mum stops the fight and gets led back inside the caravan, in one shot she is facing the right side of the doorway and in the next she is facing the left. (00:19:10)
Other mistake: Why does Boris remove and carefully wrap Franky's arm after he's cut it off? It would have been easier to cut at the wrist, therefore removing the need to take a bloody and very odd shaped parcel with you.
Continuity mistake: When Vince and Sol rob the bookies, you see Sol wipe himself off twice, on his right leg. But, when Bricktop and his henchmen are watching the video later, he wipes himself about four times, differently than before.
Continuity mistake: When Boris gets hit by the car we see it twice from different perspectives, but twice from inside the car that hits him. The way his body goes over the front of the car is completely different in both shots.
Revealing mistake: When Bullet Tooth Tony shoots Boris the Blade in the pub, the prop gun misfires on the second shot - there is no flash but we hear two shots and something falls out of the barrel revealing it to be a prop gun.