Castellari's Keoma was part of the late 1970's second wave of spaghetti westerns. It is typically considered one of the better entries in the genre, some even rate it as a classic alongside Leone's masterpieces. However, while it has clearly been attempted to make the film look stylish and sophisticated, and at a casual glance it does look pretty well made, a more in depth look shows that it falls quite a long way off the mark.
Basically, it's clear that what Castellari has is a bunch of director's tricks up his sleeve - slow motion, unconventional camera angles, subtle merges into flashbacks and so on - all of them thieved from the work of other filmmakers. That in itself is no bad thing - after all Tarantino has made a career out of doing the same - but the difference is that Castellari clearly has no idea how and when to use these techniques. He simply throws them in at every opportunity, so that they actually stick out rather than enhance the film. The most obvious example is the Sam Peckinpah style slow motion deaths after someone is shot. In Peckinpah's films it was used skilfully to highlight the brutality of certain killings here and there throughout the movie. In Keoma it is used more or less every time someone is shot - about forty or fifty altogether - totally losing any impact it might have had.
Add to this that Keoma is a completely boring spaghetti western character - basically just a hippy with a colt - and not one of Franco Nero's better performances. The dialogue is terrible. The plot is text book spaghetti western back-for-revenge. This movie doesn't really have a lot going for it.
And then there is the music, famous itself among spaghetti western fans for being almost unlistenably bad, which seems to sum up the feeling of the entire film. Quite a nice melody, but either sung in a piercing shriek by the female vocalist or an unnerving growl by the male vocalist.
In short Keoma is a perfect example of style over substance - it's all dazzling flair in an attempt to cover up a pretty poor film. Viewers should stick to the real classic spaghettis like Sergio Leone and Sergio Corbucci's work.
