They stop for a Santa standing in the middle of the road ringing a bell. Santa is brightly illuminated by their headlights. After the truck hits them they go back to Santa, still ringing the bell and still illuminated by their headlights.
Arthur Lewis received the envelope from NASA at the office informing him that he had been rejected from the program, but when he comes home his wife holds the envelope and already knows the news.
When Walter and his babysitter decide to go down the basement, he allows her to go in and down the stairs first. In the next scene, when they have come down the stairs and into the basement, he is seen coming down those stairs first and his babysitter follows.
When being followed down through the corridors of the library, they enter a main hallway where his followers are coming from two different directions. Yet just a second before, all five of them were coming from the same direction as he was.
(at around 1h 25 mins) You can see the white dots used by the CG (Computer Graphics) department to make the scar appear on Arlington Steward's face.
While it is shown to be snowing in the film, many trees are still shown to have their leaves and the grass on many yards is still green.
911 emergency services weren't available in Richmond, VA, in 1976.
When Arthur marks Arlington's car plate he does it on a post it. Post it blocks were first commercialized one year later, in 1977.
Dana's motel room has a door with a lock requiring a magnetic stripe key card. While the magnetic stripe concept has existed since 1960, it would be extremely unlikely to see a motel with such a lock before the late-1990s.
After Norma's father runs Arlington's license plate number, he refers to the vehicle as a "Town Car" but Lincoln did not come out with the "Town Car" until 1981. Up until then, and in the year this movie takes place, the use of "Town Car" was only used to denote a trim package on the Lincoln Continental. Someone referring to a Lincoln in 1976 as a "Town Car" would make no sense. It would be like describing a car as "sport package" or telling someone "It was a Ford 'Luxury Edition'".
Arlington Steward's world map shows Eritrea as a state. Eritrea was a province of Ethiopia from 1952 to the independence in 1993.
Around 33 minutes into the film when Arthur goes to unplug the Christmas tree he bends down next to a window. Just then a man's head starts to rise from the outside into view of the window. You can only see the top half of his head and it lasts for about a second, so its not part of the film. It's just out of place.
Takes place in Virgina, but Virgina cars have front and back plates.
After Norma's father runs Arlington's license plate number, he refers to the vehicle as a "Town Car". It's actually a Buick Electra.