Factual error: When the bus is shown entering Washington, DC for the competition, the shot shows the bus traveling over the Arlington Memorial Bridge with the Lincoln Memorial in the background. That bridge is on the southwest side of the city. Since NYC is to the northeast of DC, this means that to get to that bridge and enter DC that way, the bus had to drive all the way around the city and then come back in from the opposite direction. Even if the bus driver made a mistake and missed the most direct route into the city from the north, there are dozens of other ways to get to the heart of the city without adding a good 45 minutes to an hour to the trip.
Factual error: The lady hacked a tablet with he command mkdir -p on the command prompt. mkdir command is used to make a folder. (01:00:00)
Factual error: After Dr. Derry's hand is crushed by Calvin, it dangles and flops every time it is seen so that the audience can see that the bones are severely broken. However, in zero-g, the hand would float rather than swing limply.
Factual error: After the Oklahoma City casino incident, it shows a brief scene where Pierce picks up Dr. Rice. The sign in the background says "Ada 15, Oklahoma City 90" on Highway 81. That highway in Oklahoma is, in fact, a real road but it is no where near Ada. The closest area that is 90 miles from OKC would be around Duncan, which is well over 50 miles from Ada. (01:06:20)
Factual error: The finale takes place at Stonehenge. It is shown surrounded by woods, not in an open plain as it really is. It is also missing a security fence, dyke, a main road and visitors' car park. There are also hills, whereas Salisbury Plain is quite flat.
Factual error: When the astronaut is being questioned by a 3-star general, he keeps referring to the officer as "colonel", in fact the closed captioning does the same.
Factual error: No matter how sophisticated the STEM chip is, it would not enable Grey (Logan Marshall-Green) to go from a completely horizontal position to a completely vertical position in one fluid motion, without bending his knees, and he does this several times in the film.
Factual error: At the end, when the EMP explodes, the aliens are affected by the EMP but lights on the building and street lamps are still on. (01:19:35 - 01:20:15)
Factual error: When they get into Dr. Jame's lock box in the vault, inside is a camera. They turn it on and the video starts to play... despite the fact that it's been inside a vault without a battery charger for 13 years. (01:19:45)
Factual error: When they come upon the nuclear reactor cooling towers there's a wide shot that reveals there are no electrical lines anywhere near the reactor. A reactor's central purpose is to generate electricity - all "real" (non-CGI) reactors are surrounded by electric power lines and transformers. (01:20:23)