Continuity mistake: After Connor has thrown the toilet off the roof onto one of the Russians and landed on the other, he is unconscious on the ground. While Murphy is collecting things from the ground and the Russians, Connor's legs switch from straight to crossed. (00:24:09)
Continuity mistake: In the Don's house toward the end of the film (just after the saints are captured in the basement) the Don lights up a cigar and says he's leaving. When he steps outside and gets into his car, you can see a cigarette in his mouth, not the cigar he lit.
Continuity mistake: When they bring coffee to the brothers in the police station, one of the guys holds up the tray and there are three cups visible. The brothers take two and walk away. The next shot is from in front of the brothers, where you can see, over their shoulder, that there is no one holding up the coffee tray. The next shot is of the group again, and the tray is back to being held up.Nick Bylsma
Continuity mistake: While Connor is struggling to rip the toilet free, one corner of the tank lid (front right, from Connor's perspective) crumbles and a few pieces break off. Then a few moments later, the chips have vanished and the lid is whole again. (00:22:35)
Continuity mistake: The bag in which Pappa Joe Yakavetta's sandwich arrives changes in different shots. When the camera faces him, the bag is angled toward him; when the camera is behind him, the bag is angled out, away from him. (00:29:00 - 00:31:30)
Continuity mistake: In the shootout between Il Duce and the Saints, one of the brother's runs out of ammunition and the pistol locks with the slide back. The camera angle changes and immediately, without loading a new magazine, he fires off two more rounds.
Continuity mistake: In the scene where Connor is writing the hotel information down from the Russians, the position he is writing on the paper changes from directly underneath the last line to further down on the page back to directly underneath and further down again. (00:28:37)
Continuity mistake: Right as Agent Smecker shouts "There was a firefight," the Duke is shown briefly. Right before this frame, he (The Duke) already had his guns drawn, yet now his hands are down in front of him, coat closed.
Continuity mistake: In the scene where the brothers kill the mobsters in the hotel, when they are shooting the men on the counter in the back there is no case visible, but in the scene where the brother find the case of money it is there when they find it.
Continuity mistake: In the scene where Agent Smecker is doing a gunpowder residue test with liquid paraffin, his left hand starts off on the corpse's wrist, then in the next shot, Smecker's hand is by his chin. In the next shot, it is back on his wrist. In the last shot his hand is back by his chin. (00:12:31)
Continuity mistake: After the bar fight, one of the brothers pulls off the toilet and throws it from the roof. But if you compare where he throws it from, to where it hits the people, it doesn't make any sense, the angles just don't work out.