To start off, I have to say that the European name, "Going Back" really suited this movie better than "Under Heavy Fire." I'm not much of a war movie fan, but as I'm trying to see more of Casper's stuff I took a chance.
As this is a story about the soldiers, and not the War, it was much easier for me to enjoy it. It takes place in the present day, and only shows the war when being remembered, or as footage taken on the scene. It's about a US troop during the Vietnam War who experienced a tragedy by friendly fire, and they blamed their captain (Casper). In the present day a reporter / historian wanted to help the remaining troop relive this tragedy, by revisiting Vietnam and reenacting the event to help them figure out what really happened, thus "Going Back."
Most of the present day scenes felt genuine, and the War memory scenes were used strictly to clarify or enhance emotion and not just to show the War. There was an especially touching present day scene where a Vietnamese woman Captain Ramsey went to visit sings him a BEAUTIFUL song to thank, "A soldier who has lost his way."
Certainly worth my time to see.