Character mistake: When discussing the new Pope's name (Luke) at the end of the film, Langdon says: "There have been many Marks and Johns, but never a Luke." In fact, though there have been 23 Pope Johns, there has only been one Pope Mark - reigning for 9 months in 336.
Audio problem: When Langdon is in the Vatican archives for the second time and they are running out of oxygen, He uses the Swiss Guard's gun to shoot the glass. The problem being it takes roughly 0.8 seconds from the time the sound of the gun goes off to have any impact on the glass. He is no further than 5 metres from the glass, but still, this should be instantaneous.
Continuity mistake: Galileo's Diagrama has a different title when Camerlengo Strauss gives it to Robert Langdon. In the Archives, it was titled Diagrama Veritatis. At the end of the film, it was titled Diagrama della Verita.
Plot hole: Towards the end, Patrick takes the 5kt bomb into a helicopter and climbs it away to safety. The problem with that is that the helicopters have a rather low rate of climb - ~10 m/s for military helicopters, less than that for civilian ones. This is the rate of climb at low altitudes, and it is with altitude. He had less than 5 minutes to climb, which would put the bomb at most 3000 meters above the city, and more realistically, one tenth that - just about the optimum height for the bomb to inflict major damage on the Vatican city and the center of Rome.
Continuity mistake: In the collider Dr. Vetra gains access to the antimatter storage area by resting her chin in the small metal "dish" that aligns her face with the optical scanner. When she removes her face there is a small blot of blood on the side of her chin from the scientist's eyeball that the assassin ripped out (to gain access earlier). However, when we see the metal dish there is a drop of blood on the side (that ends up on Vetra's face) AND a small puddle of blood in the chin rest that dripped from the avulsed eye. Despite Vetra resting her entire chin in the chinrest none of the blood from the puddle shows up on the front of her face.
Continuity mistake: When Robert is calling for help to save Cardinal Baggia from drowning, the first person who helps Robert is totally wet when he first jumps in the water, but a second after this, his hair is totally dry when he sees Langdon, then he dives in to help.
Factual error: The text in the Archimedes document was in English, but it was modern English. I am also fairly certain that the font picked had Serifs that were not used until the 20th century (at least they picked a variety of Times ROMAN).
Revealing mistake: When Langdon first has an audience with the Camerlengo, you can quite easily see foundation on the Camerlengo's collar. This skin coloured compact is the base of any film makeup and often rubs off onto white collars if not checked.
Continuity mistake: When Langdon and the Swiss guard are out of oxygen and the guard slams a trolley against the glass, the amount of paper on the floor around it keeps changing between shots.
Continuity mistake: When the camera focuses on the French reporter standing on top of the van, he has his arm up, but in the next close-up it's down and resting by his lap.
Factual error: It is stated by Langdon that after the Pope's death, but before the successor is chosen, that the Camerlengo would become the head of the Church. This is incorrect. The Camerlengo would become Vatican City's acting head of state, however, the Church's leadership would actually be the College of Cardinals.
Factual error: Father McKenna is a simple priest and holds the post of Camerlengo, however the Camerlengo is always a Cardinal.
Continuity mistake: When Ewan McGregor runs out to the helicopter with the antimatter, you can't see the landing gear even when there is a flash of light from someone's camera in the crowd. In the next shot you can see the landing gear is down.
Continuity mistake: When they are held up by tourists, while trying to get to the second church, there is a bus just behind them. Once the tourists move, the bus has gone.
Factual error: In the beginning of the movie, we saw the Ring of the Fisherman of the dead pope, inscribed with his name: "PIUS XVI". However, the inscription should be done in Latin style, which uses "V" instead of "U". Thus the correct inscription should read "PIVS XVI". The Latin style of writing is evident in the Ring of the Fisherman that is worn by the real, currently reigning pope, Benedict XVI, which is inscribed "BENEDICTVS XVI".
Continuity mistake: When the Camerlengo parachutes onto the Vatican, the amount of blood on his nose changes from nothing to a lot between shots.
Deliberate mistake: A branding iron loses its bright orange glow relatively fast when it's out of the fire. When the police enters the room it is still very bright orange even though it has been on the floor for some time.
Revealing mistake: When the reporters say that the second black smoke is showing, an aerial panning shot of the Vatican is shown, yet the smoke remains fix as if it were a painting.
Factual error: The size of the chamber in the Vatican archives is roughly 15x10x5 meters. That's equivalent to 750,000 liters of air. Even if we divide it in half to account for the furniture and take off another 25% to account for under-pressurization, that still leaves 280,000 liters of air. Two men would consume a maximum of 20 liters per minute, if they were hyper-ventilating. That's 233 hours worth of air, or almost ten days. Langdon and the security guard were trapped there for less than twenty minutes in all.
Character mistake: When Robert and Vittoria arrive at the Vatican archives for the first time, there is a plaque on which it says "Il Processo Galileano", which is misspelled, as the right pronunciation is "GALILEIANO", with the "i" between the "e" and the "a."
Chosen answer: In reality, they would have perished from CO2 poisoning long before the room ran out of breathable oxygen causing them to simply suffocate. Without knowing the exact dimensions of the room it is impossible to give any time more specific than "several hours" for this to happen in a room as big as that one appeared to be.
Phixius ★
I just re-watched the movie, and as Langdon and Vittoria enter the room, it's mentioned to them that the oxygen levels are always kept at a bare minimum to protect the ancient tomes and documents stored there. That helps to answer my own question about why Langdon and the cop were so quickly affected when the power was shut off.
raywest ★