A much underrated film from journeyman director George Roy Hill. Hill hit the big time with his next film, The Sting, and a decade after that had a hit with The World According To Garp.
But, this is easily his best film.
Why? Because it comes from the best source material: Kurt Vonnegut's Slaughterhouse-Five, or The Children's Crusade. As many directors of note have claimed, all great cinema starts with a good script. Period.
Cinema is a visual extension of literature, rather than a narrative extension of the visual arts. This good (not common) sense reality has too often missed by fundamentalists of 'pure cinema,' but it is true, nonetheless.
The tale folows a man who becomes 'unstuck' in time- a great device that makes the man's insanity palatable enough for the viewer/reader to be able to identify with; despite the obvious things that are not true in the narrative.
The book and film differ, but only in slight ways. Michael sacks, in his only lead film role, is outstanding as lead character Billy Pilgrim, who ages over forty plus years in the film. He has just the right mix of naive-te andhumility to masque the absolute insanity of the character.
Here is a trailer of this film that just misses out on greatness: