This movie is like a lot of others made at the height of the Vietnam War - I swear Hollywood was chucking out really bad movies just to take people's minds off the war (check out Burt Lancaster in "The Swimmer" some time.) Number 1: bad songs. This is a trademark of movies made between '65 and '71. Number 2 (or 1b): use of the harpsichord. Again, a key instrument in American movies made between 65 and 71. Then, there's the anti-hero (or two of them here.) I guess by 1968 / 1969, all the good western stories had been done. (Until Josey Wales, Dances with Wolves, and Unforgiven, that is.)
This movie's writer and director must have said to themselves, "let's take the worst of the 1960's and put those characters in the 1880's." Let's imagine the Woodstock generation faced with a range war.