The film's two main filmmakers had both previously made other Vietnam War related pictures. Director Ted Kotcheff had directed First Blood (1982) whilst producer John Milius had written Apocalypse Now (1979).
Actor Gene Hackman once said of this movie around the time it was first released: "This has something to say about the Vietnam War, and about the unresponsiveness of the US Government towards people who have been affected by the war ten years down the line".
While in the destroyed village, Johnson explains that Ypres is a town in France where mustard gas was used for the first time by the Germans. Ypres is actually in neighboring Belgium.
When Gene Hackman's character arrives to pick up the weapons and the police officer tells him that the guns will be confiscated, during two shots we see the truck driving off behind him.
When Kevin Scott and Mr. Jiang are lying on the hilltop, overlooking the prison camp, they have a verbal exchange as to whether the choppers are actually coming. The camera shifts back-and forth several times between Scott and Jiang. During the course of this dialogue, however, Jiang is - without
ever changing his position - shown alternately holding a recoilless rifle, or a rocket-propelled-grenade launcher.
Col. Cal Rhodes: If a man were to know the end of this day's business 'ere it come. But it suffices that the day will end and then the end be known. And if we meet again, well then we'll smile. And if not, then this parting was well made.
Yes, the concept that American prisoners of war were still being held in Southeast Asia was extremely prevalent in the early 80s (the Vietnamese communists not releasing some French prisoners until 16 years after the Indo-China war). It was taken seriously enough that ex-Green Beret Colonel Bo Gritz organised a private rescue mission (on which this film is based) but was persuaded to call it off by the US government who were organising their own rescue attempt using the Delta Force. In his autobiography former Delta Force member Eric Haney (writer and co-creator of the series The Unit) states that this mission was effectively scuppered when Gritz held a news conference revealing his own efforts in order to draw attention to the issue. Gene Hackman's character is widely thought to be based on Gritz whilst Robert Stack's is based on Texan billionaire Ross Perot who was deeply involved in the Vietnam MIA/POW campaign. In 1993 a meticulous inquiry by Vietnam war veteran Senator John Kerry and former Vietnam Prisoner of War Senator John McCain concluded there was no proof of any prisoners being retained in Southeast Asia after the end of the conflict and the subsequent opening up of Vietnam following the collapse of the Berlin Wall has not revealed any evidence of US servicemen being held against their will.