Loved it as a kid, the three stars is generous but it's fun enough, helped by decent production values (Oregon location, rapids, bars, extras, a mini flood) and a classy support cast: James Sikking s in there, John Hillerman. Tim Matheson is full of handsome confident swagger that promised a stardom which never came; the bloke from Porky's seems a little lost, Stephen Furst is fat, the nerd is an alcoholic which is interesting. Jeff East is an ideal villain. Jennifer Runyon is very sweet as the love interest - she and her friends are very sexually aggressive and not punished. Blaine Novak's Coyote-style army villain entertains. Cheap Trick didn't like its theme song but I felt it was fun.
I'm not objective about this film but it's fun. One of Sam Arkoff's post AIP efforts.