My mother gave me this insight (she's a genius). This movie is an allegory of the US and the struggle against first the nazi's and then communism. See dialog between young Barr and the Russian who shaves him. Calls him Mr. America. Says they will be cursed and do not truly know each other. Will be enemies? Gin versus vodka. He kills hitler, but does not feel he's accomplished his mission. The man killed did not kill the idea. See the rock he cannot get out of his shoe. Fast forward. Flag pin (American government) asks him to kill THE Bigfoot, not a Bigfoot. Something that will destroy the world. A virus that will spread to the whole world (communism). Must be nuked. Barr is immune (the American soldier/patriot). Others are too old or too young. His (the bigfoot's) footprint is not THAT big. He breaks a pinky and loses an ear (the curse from the Russian, but not fatal blows). The Bigfoot is not an animal. It is a zombie-like evil. He tries to show mercy (they won't get your body buddy) only to have the evil turn on him again. Evil must be met with brutality. Once he is vanquished, the American soldier feels his mission is complete (rock out of shoe). The soldier (uniform and medals) was buried. See dates on tombstone. Very close to Russian revolution then fall of Soviet Union. However, the "box" was dug up again for the American soldier to stand guard "one more day". The fight does not end. The American soldier cannot rest. So many other symbols. Just food for thought. I can't find anything to corroborate, but everything fits. Very thought provoking and enjoyable film. More there to be uncovered with the brother and girlfriend (those left at home). Sam Elliot is excellent.
