Near the end of the movie when Madeleine White visits Mr. Case at the barber, Mr. Case says "Yes, it was sixty years ago, I was young and ambitious", you can very clearly see his lips mouthing "fifty" instead of "sixty", though the audio says "sixty".
When the ring case in the safety deposit box is opened, the Cartier logo is smaller, with "London" and "Paris" visible under the logo. Later, when Detective Frazier shows the ring in the box to the mayor, the logo is a different Cartier logo.
Miss White's assistant's hair is unkempt and has hair forming two loops sticking up toward the back of his head when he tells of Mr. Case's phone call. In subsequent shots his hair appears combed with no hair sticking up.
When Madeline and Case are talking next to the river, Case is standing with his right shoulder towards Madeline. In the next shot, he is turned dramatically so his left shoulder is towards her, and then it is back the other way.
When Dalton Russel is talking about the game with the boy in the vault, the bottom shelves behind them are of different heights. Just one minute later he stands alone and remove his mask, and the shelves are at the same height.
The van used by the bank robbers is a Chevrolet Express which utilizes daytime running lamps which cannot be turned off. The lamps are illuminated when Dalton first drives off in the van and again at the bank. However, when the van is driving over the Brooklyn Bridge, the lamps are no longer illuminated.
When the NYPD ESU is initially setting up around the bank at 20 Exchange Place, Manhattan, FDNY Engine 332 arrives on the scene. FDNY Engine Company 332 is based in Brooklyn, on Bradford St., not Manhattan.
In the last scene, Frazier empties his pockets to end the day. He takes his magazine out of his gun to disarm it, but we see there is no ammo in the magazine. A detective would never carry an unloaded firearm.
Although Russell disabled the security cameras before the rest of the robbers entered, Detective Frazier could've easily determined who the perpetrators were (with the exception of Russell who left separately) through simple process of elimination. Anyone who exited the bank but was not shown entering it on the security footage is likely involved.
During the final conversation between Detective Frazier and Arthur Case, all of the discussion about the diamond ring was added later in editing. When Frazier mentions the ring, it is clear that the video has been slowed down, and his mouth does not match up to the words being said. In addition, a picture of a hand with a ring on the middle finger was inserted into the scene - first moving up into the shot, and then moving down off screen. As Frazier turns his head away, additional dialog was added about his intention to investigate the ring's history.
At the end of the film, Dalton is leaving the "storage room". On the left side of the screen, one can see a set of doors that have glass over them, and a short distance back, outside windows with sunlight streaming in.
The distance is too short to match up to the apparent length of the storage room as seen in the earlier parts of the film. There is also no indication that there could be any ceiling over that space.
As the ESU team is approaching the vault during the Capt's break-down of their entry, the Sgt.'s (Guy on the left of the screen) weapon fires two-three times before any visual is made of Dalton. Once as he comes around the column and another time as he walks toward the vault. It appears to be a mistake on the actor or malfunction of the weapon.
The goof items below may give away important plot points.
The robbers sent their demands written on a desk drawer from the bank. Later on Detective Frazier discovers that the drawer was bugged but this time the writing and capitalization is different. For example "SemTex" changed to "SEMTEX".
When the bank robbers first walk into the bank they are all wearing painter outfits. Upon bringing all the hostages into the basement the robbery crew make them all take out their cell phones and keys, and remove their street clothes, which the police all find in the bank after the robbery. While the police interview each hostage to see if they knew who was who, they supposedly had to just match each hostage with their possessions. But Steve, Stevie, and Stevo-O undoubtedly put their own street clothes, cell phones and keys in the bags along with those of the hostages, to claim as theirs after slipping out of the bank with the hostages.
When Frazier is in the bank to negotiate, he says "What happened? Couldn't you open the vault?" As he says this, the vault's door in the background can clearly be seen and is wide open. This comment is deliberately said in front of the open safe, as Frazier is being ironic. Much of the dialogue throughout the film is ironic, especially Frazier's. He had already commented that he realized the goal of the thieves is to gain time, and this is his way of saying to Russell that he knows.
In the scene where the 'hostage' is dragged kicking and screaming by his ankles through the rooms of the bank, he pulls a pile of books over that are stacked next to the doorway. Later in the film when the police storm the building, the books are neatly stacked back at the side of the door. However, it is entirely possible that either one of the robbers or hostages stacked the books back up during the course of the film.
The police conclude as that no money was taken, "no crime was committed." However, armed robbery is itself a crime, even if nothing is taken. So is taking hostages and controlling the building illegally for several hours, as well as other subtle misuses of bank property. "No crime was committed" is an unrealistic description of what happened.
The cops are supposedly fooled when the gang play part of a speech in Albanian by the late Enver Hoxha to fool their listening devices. But even though they don't know the language, they ought to notice that it sounds like a monologue by one man rather than a possible conversation between four bank robbers, one of them female.
The man hides out in an extra room made at the end of the bank's supply room. But this depends on none of the bank staff noticing that the room has suddenly got shorter. The placements of items would also change. Regular employees would include at least one person who would notice.
When the hostages are lying on the street outside the bank and are being put in PlastiCuffs (also called FlexiCuffs), you can see that several of them are not tightened, so they can just take their hands out of them if they wanted to.