Factual error: The idea that anyone survived living in Pripyat Hospital is absurd. The uniforms of the doomed firefighters were stored in the basement and are so radioactive that anyone straying downstairs for more than 45 seconds has about a week to live. The ground and upper floors are far less radioactive but prolonged exposure - in other words, living there - would be fatal. Nobody could survive on the grounds for more than two or three months without receiving a lethal dose of radioactivity. Incidentally, prolonged exposure to radioactivity doesn't turn you into a deranged zombie - it turns you into a corpse.
Factual error: The type of surgery shown made by the machine transversely cuts the rectus abdominis muscles. Besides not being a standard surgical incision in order to "remove a foreign body" as stated, it seriously damages important muscles of the abdominal wall making any immediate active mobilization of the trunk virtually impossible, even under strong analgesia.
Factual error: In the scene where Arthur first enters the house and starts going through paperwork, there's a shot of Nathaniel Drablow's death certificate which shows 'body was not recovered' in the box next to his cause of death. Such a thing would not be written on death certificates of the time - that box is reserved for 'Signature, description and residence of informant', a heading which can partially be seen as the camera pans across the certificate. For the death to have been registered, an informant's signature would have to have been there. (00:20:05)
Factual error: At the start of the war, it says Fort Sumter 1861. However, on the battlefield we see the US flag with 35 stars. In April 1861, there were only 33 states.
Factual error: Semi-automatic guns don't just click empty, like they do in a lot of movies. The slide would lock back until you manually cock the gun. Yet in the corridor of light scene, this is exactly what happens: Alice's gun just clicks when it's empty.
Factual error: Detective Sebastian fires a total of 7 rounds at the Antigen van in the parking garage - three at the driver, two at the front-left tire, one right before the van nearly runs him over and then one after it passes him - without reloading, yet the Taurus Judge revolver he is using is designed to only hold 5 rounds in its cylinder. Later, after Sebastian has reloaded the revolver, he fires 8 rounds at Dr. Lane, again without reloading.
Factual error: When the main character goes into the church, she looks at a picture from 1989 labeled "annual picnic". In the picture a boy (next to the main character's mother) wears a hat with a DC (DC Shoes) logo on it. DC Shoes was established in 1993. (01:00:00)
Factual error: When the underground garage of the market is flooded, the car that Kyle and Heather are in does not flood. A car is not water tight like a submarine. Even though the water does not cover the top of the car, water would flood the entire car within minutes.
Factual error: When Dave shoots Justin 8 times, he empties the magazine of his semi-auto handgun, but he continues pulling the trigger, and the gun clicks several times. Semi-auto handguns do not "click" when they are empty, because it's impossible to pull the trigger. Also, the slide of Dave's handgun does not lock in the open position when the magazine is empty, as it should.
Factual error: The poster displayed in Sally's room is not from 1974. It shows a series that was released in 1997.