When Jayden makes his first recording with ARI on the wasteland where Jeremy Bowles' body is discovered, he notes that date as October 2011. Later, when Madison checks into the seedy motel, the clock behind the receptionist displays the year as 2012. Pre-release media such as the game trailer do show this clock displaying the correct 2011 year.
If Ethan is arrested and interrogated by Blake, Norman has the option of interfering by shoving Blake and then punching him. Blake will then force Norman out of the room by threatening him with his gun. It is against police protocol to carry a sidearm into interrogation, for fear the suspect might get possession of it. This rule is deliberately violated by Blake to demonstrate further corruption. Other examples of disobedience committed by Blake include trespassing on a suspect's property and using excessive violence towards them. This is used to make the player consider Blake a possible suspect in the case.
The game is supposed to be set in the United States, yet Ann Sheppard's hospital room has "Type-G" wall-sockets next to her bed. These sockets are meant for 220-240V/50Hz European voltage, and would never be found in an American hospital.
The game is supposed to be set in the United States, but some of the cars that are featured have European-style license plates. The most obvious example is the sports-car Ethan picks up in "Chapter 18 - The Bear".
The goof item below may give away important plot points.
At the end of the game, in the news broadcast, it mentions Scott Shelby's age as 48 years old. However, when we are shown his headstone, it gives his birth and death dates as 1967-2011 which would make him 44 years old at the time of his death and not 48.