Nice cover and beautiful art by Renato Casaro. Anyway, When I look at it, I really miss the presence of Lee Van Cleef, or even Gian Maria Volontè... Klaus Kinski's character wasn't so important in that film.
You said everyting... great cover, I love Renato Casaro's cover art, but actually, Kinski's is a (memorable, not doubt) side character in the movie, while Lee Van Cleef's Colonel Mortimer is (along with Eastwood of course) the main character of the movie.