A kind of metaphysical thriller about a man (Lee Marvin) who tries to get some money back from some crooked characters who obviously don't want to give it back. Guns and fights are very much to the fore, and Marvin gives a very good performance of the man obsessed with his revengeful quest. At the time of it's release (1967) it must have seemed a fantastic film, but of course it has spawned a large collection of films that have tried to copy it in one way or another. It's a top class gangster film, very well directed by John Boorman with some brilliant cinematography from Philip H Lathrop.
Nobody tops Lee Marvin in an action film, and this is arguably his best ever. The plot and script are also top notch. For a 60s film, this has worn extremely well.
I urge you to see it!