The invading army was originally Chinese. It was changed to North Korean in post-production, to maintain access to China's box-office.
The encoded messages on Radio Free America are identical to those in the original Red Dawn (1984).
The film was shot and completed in 2009, and originally scheduled for release on November 24, 2010. It was shelved for almost two years, due to MGM's financial troubles.
When the group is talking about things they miss, one person says Call of Duty 4: Modern Warfare (2007). One stage of Call of Duty: Modern Warfare 2 (2009) is called "Wolverines", taken from the original movie, in which Russia invades America.
Filmed in the Fall of 2009, halted by MGM's bankruptcy in 2010, and the controversy over using Chinese soldiers. The Chinese soldiers were changed to North Korean before releasing the film in 2012.
Early drafts of the script had the protagonists fighting Middle Eastern terrorists.
The changes to the film's antagonists reportedly cost less than one million dollars. They involved changing an opening sequence summarizing the story's fictional backdrop (dropping the original storyline of Chinese "repossession" after the U.S. defaults on loans, for a North Korean invasion), re-editing two scenes, and using digital technology to change Chinese symbols and dialogue to Korean.
Chris Hemsworth is younger than Adrianne Palicki even though he plays the older Marine and she's the younger high school student.
Jeffrey Dean Morgan and Adrianne Palicki appeared in Supernatural (2005). Jeffrey was John Winchester, and Adrianne played Sam's girlfriend Jessica.
The invading army in the original 1984 movie was the Soviet Union, which no longer exists, and Cuba. North Korea was chosen as the enemy in this updated version.
The film features propaganda pamphlets, posters, and banners featuring People's Liberation Army symbols, such as the August 1 star. The posters attempt to garner support for a Chinese occupation, with slogans such as "Rebuilding Your Reputation", "Repairing Your Economy", and "Fighting Corporate Corruption".
The closed Notre Dame High School in Harper Woods, Michigan (Greater Detroit) was used as a filming location. The school cafeteria was used as the catering hall for the employees.
In the same year, Josh Hutcherson appeared with Chris Hemsworth's brother Liam Hemsworth in The Hunger Games (2012).