Sergio Leone's first western was seminal for the genre. It drew the outlines of the perfect Italo Western.
His second work is still a Spaghetti Western, yet, instead of following the heart of this genre, it tries to reach the outermost outlines of it. Sergio Leone sometimes uses shots and cuts just as weird as in Citizen Kane. It's sort of an experimental film, only you can still see all the characteristics of a great Italo Western.
The story is as experimental as the rest of the movie.
It starts off like the normal western startup, with some fine old-fashioned bounty hunting.
But then the experiments start. First of all, there aren't only two different parties (El Indio vs. Clint Eastwood), there are three, as Lee Van Cleef joins in as rival bounty hunter. Then, after the two heros teamed up, they join the bad guys after failing to thwart their plans of robbing the bank. And then again their plans get discovered and they get captured and bound, just to be released by the master bad guy himself.
At the end, there is - of course - the great showdown and the villain gets killed, so the film returns to the known perimeters of the genre. Yet the taste of the experimental remains.
All in all a great film, that isn't quite the standard and therefore really refreshing.