When Stan is about to shoot down Gabriel's fleeing helicopter, his shadow is cast to the left of the screen, indicating that the sun is far to the right of the camera. However, the helicopter itself casts its shadow right in front of Stan, indicating that the sun is almost directly behind the camera.
The Finnish hacker has is a mixture of different versions of German passports. There used to be green German passports, but that was before the time of computer-readable plastic-cards inside the passports. Since German passports have this card inside, they have always been red.
The $400 million in DEA money is said to have grown, "with interest", to $9.5 billion in 15 years. That would represent a compound interest rate of over 21% per year, which is unrealistic. At 12%, the money would have grown to a little less than $2.4 billion. At a more realistic 6%, it would be about $981 million, or a little over one-tenth of the value claimed in the movie.
In the film's opening speech, Gabriel Shear discusses Dog Day Afternoon as being a "1976" work of "fiction" that didn't "push the envelope" and showed Hollywood's "lack of realism." Dog Day Afternoon was a true story, not fiction, depicted realistically. The film ended the way the true story ended. It was released in 1975, and the film's action takes place in 1972.
US broadcast TV versions use alternate "top on" footage of Ginger's sunbathing scene (see Alternate Versions) but only for the front view; over-the shoulder shots use the theatrical take, causing the bikini's neck strap to vanish and reappear throughout the scene.
When hacker Axl Torvalds presents his passport to the customs officer it clearly shows the Bundesadler watermark. The second customs officer then finds the second passport which also has the Bundesadler watermark. Yet, when the first customs officer holds up both passport, one has the watermark and the other doesn't. The unmarked passport was not seen until that moment.
When Stan drops his daughter off, and the FBI agent gets in, after Stan breaks the agents nose he backs into the right door of the FBI car denting it and shattering the window. After they roll down the hill, and Stan rolls over the car, the right door is undamaged.
When Ginger first arrives at Stanley's trailer, as she pulls up and gets out, he puts a golf ball on the tee and stares at her. Then as she comes up to him he puts a golf ball on the tee again and stares at her as if he just noticed her.
In the first scene with Stanley and Ginger, she tosses him an expandable envelope full of money and tells him that it contains "a hundred grand." But the insert shot of its contents shows only $40,000.
Marco holds a gun to Stanley's head in the nightclub hacking-under-pressure scene. In the shots looking upward at Marco, he is holding the gun with just his right hand. In the closeup shots of Stanley, Marco is holding the gun with both hands.
After driving his daughter home, Stan reverses his car and hits the door of the FBI agents' car, breaking its passenger side window. When the car later catches up to him, you can see that its door and window are still in perfect shape.
As Gabriel walks away from the trunk of his car and starts firing his machine gun, the trunk is open and has bullet holes. In the next shot (taken from behind the car), the trunk is closed and has no damage.
In the coffee shop, closeups of Shear show the reflection of a bright white rectangular reflector in his sunglasses. In the reverse shot, from his point of view, there is only a window with a view of the street.
When Stanley first goes to Gabriel's house and is standing by the pool, there is a clear shot of many skyscrapers in what appears to be downtown Los Angeles. However, when the FBI is doing surveillance on the house during the day, it is suddenly on a cliff overlooking the Pacific Ocean with no skyscrapers in sight.
The conversation with Senator Reisman and his aide near the beginning of the film is supposed to be in Washington D.C. however, the Westin Bonaventure Hotel in Los Angeles can clearly be seen on the left side of the screen before the characters walk outside.
When the computer shows money being transferred into banks all over the world, one of the destinations in South America is spelled "Columbia". The South American country is spelled "Colombia". Additionally, the location on the map is too far to the east to actually be in Colombia - it looks more like the middle of Brazil.
The bank in "Monte Carlo" at the end of the movie displays the French and European Union flags outside and in the foyer. Monte Carlo is in the Principality of Monaco a separate nation to France with its own flag. Monaco is not part of the EU. The building is in Nice, France.
At almost the end of the movie, when the glass door of the banks computer mainframe is opened, you can clearly see that the network cables between the Dell servers are bonded together with plastic TY-raps. This is faulty, the cables should be bonded together with Velcro. Plastic TY-raps can be tightened to hard, which changes the characteristics of the cables.
When they all leave the bank and get on the bus. Gabriel says "No one wants a repeat of what happened this morning. Keep your distance. Clear the airspace for five miles." Ok, so how can the big helicopter get in that restricted airspace, then get to the freeway to pick up the bus without being intercepted? Even if it was parked on top of a building 7 blocks from the bank before the bank robbery/hostage incident took place, as soon as it took off, LAPD helicopters would order it out of the area, by force if they had to.
When the FBI agents are watching Gabriel and Stanley, one of them looks through the viewfinder of a camera (Canon XL1s) with a large lens. It is clearly visible that the viewfinder cable is not connected with the body of the camera.
During the surveillance of Gabriel's house, when the pictures later sent to the senator are taken, we see three freezes of the image, ostensibly the pictures being taken - between each freeze frame, the W-T indicator in the bottom left corner of the image moves. That indicator shows the state of zoom of the camera (Wide-Tele), so since the indicator moves towards the W, the picture should zoom out, which it doesn't.
Just before Gabriel executes the Senator, he claims that President Thomas Jefferson once shot a man for treason on the White House lawn. No such incident happened in Jefferson's administration. (The Senator seems to be starting to point this out when he is killed.)
At the end of the movie, the voiceover radio report of the terrorist's death refers to an attack on the U.S. Embassy in Istanbul. Istanbul has not been the capital of Turkey for nearly a century. A U.S. diplomatic presence in Istanbul would likely be a Consulate-General. An attack on the U.S. Embassy in Turkey would have occurred in Ankara.