As a Vietnam veteran, I just never cared for any of the films that were considered anti-Vietnam or anti-war period. In this instance, I also don't like Christopher Walken at all.
I didn't like this movie, for the reason stated above, nor did I like Brando's "Apocalypse Now", for the same reason.
My favorite movie about Vietnam was "Hamburger Hill", which I thought was excellent and very believable.