I realize you have to suspend disbelief to some extent while watching a movie like this, but a literal handful of untrained, inexperienced teenagers just mowing down dozens and dozens of well-trained and well-equipped professional Soviet Army troops without taking any casualties at all?
Not without nuclear weapons. The Pentagon studied the problem in 1962, fourteen years after we got involved, and concluded that it would take one million men ten more years to subdue Vietnam. When Kennedy got the report he ordered US troops out of Vietnam. If you think it is so easy, why not enlist and get a taste for yourself.
I loved it then, I love it now, it gets too much hate from revisionists.