Continuity: When Il Duce steps in front of the Taurus to confront the MacManus Brothers and Rocco, the rear wheel is shown without a hubcap. But in the next shot where Il Duce is shown standing in front of the Taurus in full view, both wheels have hubcaps on them.
Revealing mistakes:Sean Patrick Flanery's stunt double is obvious when he is carrying the toilet to the balcony of the apartment.
Crew or equipment visible: When they attack the Russians in the alley, the shadows of a boom mic and of a crewmember's head fall are visible on the right-hand side of the screen.
Continuity: Rocco gets punched by Chekov at the bar and the next day at Papa Joe's he has a black eye. The following day, the black eye is gone.
Continuity: The angle that Roc/Funny Man is pointing his gun at the priest in the confessional booth.
Audio/visual unsynchronized: When Connor and Murph are waiting for Rocco to call them, Murph slams his hand down on the phone when he picks it up. The phone has an electric "ring", but when Murph slams his hand down on it, we hear a bell. A phone with an electric ringer would not have any kind of bell inside it.
Continuity: When the crime scene at the Copley is being investigated, the coins are removed from the dead man's eyes. A second later they are back.
Continuity: Throughout the scenes where Connor and Murph have been captured by Yakavetta at his house, the blood on their faces changes between shots.
Continuity: When Connor calls the number on the Russian's pager we see him write down Copley Plaza a few seconds before we hear the guy on the other end of the phone say it.
Continuity: During the alley investigation, the sunlight and shadows against the building change dramatically as Smecker looks down the alley. First only a strip of sunlight is on the wall, then a huge triangle a few seconds later.
Errors made by characters (possibly deliberate errors by the filmmakers): Rocco is referred to as "Mushmouth from Fat Albert" when he puts on the hat with holes cut in it. It was "Dumb Donald" in "Fat Albert and the Cosby Kids" (1972) who wore a hat with holes over his face.
Continuity: When Rocco is insulting the Russian's mother in the bar, his line continues without interruption, despite him getting punched in the face.
Audio/visual unsynchronized: When David Della Rocco is hit in the bar by Ivan Checkov, his sentence is finished after he's knocked out.
Continuity: In the scene where Connor, Murphy and Rocco are cauterizing their wounds with an iron you see Murphy being held down first, the sleeve of his shirt is ripped open and Connor is applying the heated iron. The next person to be held down is Rocco, Murphy is doing the burning and his sleeve is now in tact, with a bloodied bandage around it. When it's Connor's turn, Rocco does the burning and Murphy holds him down, his sleeve is once again ripped.
Factual errors: In the credits, the name of the Fairmont Hotel Copley Plaza is misspelled as "Coply".
Continuity: In the scene where Rocco shoots the cat, when they're all standing in the doorway to the living room, Murphy has an unlit cigarette in his left hand. They cut back to the cat on the wall, and when it cuts back to them, when Murphy says, "I can't believe that just fucking happened!", he doesn't have a cigarette any more.
Continuity: Smecker's tie during the investigation of the hotel room.
Audio/visual unsynchronized: As Agent Smecker walks behind the column in the squad room, his voice continues, but his lips aren't moving.
Continuity: During Smecker's investigation of the Russian mobster's deaths, he places a bottle of some liquid he uses on the Russian's hand on the ground about a foot and a half in front of the Russian's body. When the close-up of the Russian's hand is shown, however, the bottle is much closer, then it returns to its previous position on the ground when the shot switches again. Then as Smecker stands to investigate the bullet hole farther down the alley, he leaves the bottle on the ground. The bottle disappears in the next shot as the camera zooms out away from the body.
Continuity: When Smecker drips the Paraffin on the Russian mobsters hand it turns black. The next shot however, it is red still.
Continuity: The Russian mobster with the bandage on his head in the alley's arms change positions throughout the scene.
Continuity: During the beginning scene in the church you see the church completely filled from the rear of the church. Later when you see the congregation from the front there are less people then what you saw before.
Factual errors: Il Duce is being held in a "maximum security" prison. When the guards are transporting him they all have shotguns drawn. In real life, maximum security prison correctional officers do not carry guns within such a close range of the inmates, but from a bit of a distance so as to not allow for such easy access of a firearm for the inmates. The officers in close range of the inmate will, however, most likely have a can of pepper spray pointed at said inmate in transfer at all times.
Miscellaneous:Norman Reedus has his name "Norman" tattooed over his heart, and in the apartment scene when the Russians come to get our boys, his robe falls open and you can clearly see the tattoo.
Continuity: When Murph is stripping the Russians of weapons and money, the tie on his bathrobe keeps switching positions in the shots.
Revealing mistakes: In the hotel, when Connor and Murph stick coins of the eyes of the first dead Russian, he blinks twice.
Continuity: The position of Connor's legs as he is laying on the ground after saving Murphy from being shot changes a few times as Murphy is searching the dead Russian.
Continuity: When Il Duce steps forward, he is standing by the middle of the car, looking up with two pistols out. In the next shot with Paul Smecker on his knees, Il Duce is standing at the back of the car, looking down and his guns hidden by his coat.
Continuity: When the Russians break into the brothers' apartment, Checkov hits Connor in the left temple with his gun. When Connor is handcuffed to the toilet, he is bleeding from the right side of his head.
Continuity: When the brothers leave the gun store, they are wearing sunglasses, which disappear for the next few shots; even when they walk down the stairs into the basement. When they step into the elevator, they carefully take their sunglasses off.
Revealing mistakes: When Agent Smecker is investigating the alleyway crime scene it shows that one Russian had boot prints on his back, but in the flash back to the crime scene when Connor jumps on his back, his feet do not make contact. Also, he steps *over* him and never on him when retrieving the weapons, money and pager. At no point did his boots ever make contact with the Russian's back.
Continuity: When Il duce is about to fight the saints outside of the house, the car he is standing in front of is missing a hub cap, next shot it is there
Factual errors: In the opening church scene, the priest is reciting the Lord's Prayer but, contrary to Roman Catholic liturgy, none of the parishioners join in. Furthermore, the Lord's Prayer is recited well *after* the homily.
Factual errors: Also in the opening church scene the Protestant, rather than the Roman Catholic, version of the "Our Father" (or "Lord's Prayer") is being used (the Catholic version does not have the "For Thine is the kingdom, the power... etc.", but uses a different doxology slightly later in the liturgy).
Continuity: When Rocco is in the confessional with the priest, Connor enters into the confessional opposite Smecker. Connor then uses his finger to open the divider through the screen. You can clearly see him push the door to his left, the shadow on the wall next to him also moves sideways. Next, you see the priest open the divider to Smecker's confessional by lifting it straight up.
Factual errors: The last goof on the goof page of Boondock Saints is incorrect itself. It says that the correct translation of "filii" would be daughter, but that is incorrect. Filius has a genitive form of the word, which shows it to be in possession of, and that form is filii, so filii means "of the son."
Continuity: When Conner is ripping the toilet out of the ground, the top gets chipped at the front and at the side. But when you see the top view of him carrying the toilet it's not chipped.
Continuity: When Connor is straining to get free from the toilet he's cuffed to, the sash of his robe has fallen out of the left-hand loop of his robe and is only being held by the right-hand loop that is facing the camera. When he walks out onto the rooftop with the toilet a moment later though, the sash is strung neatly through both loops.
Continuity: When at the Lake view, Rocco fires the first bullet through the left side of his jacket. For the rest of the movie there is no hole in the coat.
Errors in geography: Rocco's shooting at the diner is said to take place on "Comm Ave", short for Commonwealth Avenue. The news caption says the shooting took place in South Boston. Commonwealth Avenue runs east-west through Beacon Hill, the Back Bay, Fenway, and Allston. It goes nowhere near Southie.
Factual errors: The Boston Police Department patches that are seen on uniforms and ballcaps are not the right color or shape of the actual BPD patches. The actual BPD patches are conical and blue with yellow lettering that says "Boston Police, 1630 AD".
Errors made by characters (possibly deliberate errors by the filmmakers): When the Monsignor relates the story of Kitty Genovese, he mentions that the attack took place "almost 30 years ago" and "in broad daylight." The attack occurred in 1964, a full 35 years prior to the movie taking place, and at 3:30 AM (albeit under streetlights). These errors may have been purposeful to demonstrate that people's indifference continues, and is even greater now.
Audio/visual unsynchronized: During that rant given by Agent Smecker at the Boston Police Department about an information leak, his line, "That's just what we need now." is obviously dubbed.
Errors in geography: When in the alley at the first crime scene, the camera points towards the exit, to the main street. We can see, clearly visible, the front sign of a "Henry's" camera store. This franchise only have stores in Canada, so it wouldn't be possible to find one in Boston, MA. This reveals that part of the movie has been filmed in Toronto, ON.
Errors in geography: When Connor is standing above the apartment building getting ready to drop the toilet down on the Russian mobster, there is a second where he looks ahead and Toronto's CN Tower is clearly visible in the top right section of the screen. This indicates that this scene in the movie was not filmed in Boston, in which the movie was supposedly set.
Errors in geography: After Rocco talks to Murphy on the pay phone he crosses the street in order to enter the Lakeview Lunch Café and as he does the camera pans a view of the street in which a TD (Toronto Dominion) Bank is situated on the right hand side on the street, mid-screen. This obviously indicates that this section of the film was also shot in Toronto, Canada because that is a Canadian Bank chain and would not be found in Boston, MA.
Errors in geography: After the shootings take place in the Lakeview Lunch Café, when the news anchor is reporting on-location, a shot of the establishment's sign is clearly visible in which it states: Lakeview Lunch Café, Est. 1947, L.L.B.O. The L.L.B.O is the hint here because it stands for the 'Liquor Licence Board of Ontario'. The Liquor Licencing Board of Ontario would have nothing to do in Boston, therefore once again giving away that this part of the film was shot in Toronto.
Continuity: In the hotel scene with 9 dead Russian mobsters, agent Smecker puts his hands in his hair, with blood on his gloves. (the policemen are seen to wince when he does this). Later on, he is looking up at the hole in the ceiling, and you can clearly see that there is no blood in his hair.
Factual errors: When the bar fight scene begins the brothers are telling the Russians some phrases in Russian, which are translated in subtitles. Actually the words that they are saying not only don't respond to the translation, they are mostly made up and make no sense at all.
Factual errors: When the boss of the Russian crime syndicate is first shown, a sign telling the viewer who he is appears. It says "Yuri Petrova", while Petrova is a female Russian surname. (In Russian male and female surnames differ, for example: Petrov - Petrova)
Errors made by characters (possibly deliberate errors by the filmmakers): When asked if the brothers are armed and dangerous, Agent Smecker says they aren't armed "if they had guns, they would have used them". However, he found evidence of the Russians using guns, and the guns are gone. Logically, the brothers have the guns.
Crew or equipment visible: When Connor lifts the toilet away from the wall and his wrists start to bleed if you look closely at his right hand you will see him squeezing blood out of what appears to be a sponge making more blood pool on the floor that that which is coming out of his wrists.
Continuity: In the scene where Rocco rushes into the room and is packing: he grabs some albums out of the rack and packs them. In the next shot they are back again. Shortly thereafter the albums are again gone. The actual selection of albums remaining on the rack varies also.
Plot holes: Arriving at the crime scene, Smecker asks one cop his name. After he examines the scene with the headset on, he suddenly knows everyone's name.
Continuity: While Smecker is chastising the precinct for leaking the story to the press, right before he says "They're angels!", his hands come out to his sides. From the front, they are shown palms up, but from the back, they are palms down.
Audio/visual unsynchronized: During the bar fight, right before the bottles are broken over the Russian's head, Connor is heard saying "He can take care of himself", but his lips don't match the audio.
Factual errors: Light bars on Boston Police cruisers don't have red lights; only blue and white.
Continuity: As Connor is carrying the toilet onto the roof, you'll notice that before he drops the toilet, the toilet does not have a seat or lid. After the toilet hits Checkov, it begins to turn towards the camera and a closed toilet lid is fully visible.
Revealing mistakes: The gun that supposedly shoots the cat remains in place on the table, even though no one was holding it - the recoil would obviously have knocked it off the table.
Continuity: In the alley scene with the Russians, when Connor throws the toilet onto the Russian holding the gun to Murphy's head, he scares and fires a bullet, which presumably drills a hole into the dumpster. However, when you watch closely, you can see the gun being fired while aiming downward at the floor, not at the dumpster.
Plot holes: When Smecker tells the cop to "find the manager of this building," the cop is only out of the scene for 90 seconds, yet he comes back in to say that there is no manager present, and that he spoke with a lady on the fourth floor. The cop barely had time to get up to the fourth floor at a run, let alone speak to someone!