Over twenty classic Hollywood western movies were quoted, referred to or punned on.

The music was composed before the filming began, recorded and played back while the scenes were being filmed. The voices were looped after filming.

Henry Fonda was the major coup for Leone, as the actor had never played a villain in a major film before.

The film begins with a hard hit in the gut right off the bat.
Boredom. Minutes of just plain nothing. Water drips, buzzing flies and three bored men.

Once Upon A Time In the West is full of space and time. Yet it is claustrophobic in it's closeups and interior shots. There is a sphincter-tightness to every scene, menace aborning. Every major character is a victim.