"Odd sonorities always have been innate to Morricone’s magic. Listen to the distorted keyboard notes at the beginning of “Scherzi a Parte.” Alone they would become tiresome after a few bars, but used sparingly against more traditional instrumentation the squonking cartoonish noise is a marvelous example of how well electronic sounds can mesh with acoustic sounds. The most amazing track on Duck You Sucker (aka A Fistful of Dynamite or originally Giu La Testa) is the nine-minute “Invenzione per John” (or “Inventions of John”), which deserves to be dubbed “Reinventions of Ennio.” Morricone reprises his theme but extends it through free form abstraction by overlapping melodic ideas where every element seems out of sink with the other. Morricone deconstructs his musical thoughts and along the way discovers countless variations on his theme. It’s the most hypnotic nine minutes you’re likely to find on an Italian western score. It’s nothing short of brilliant."
– from Chapter 4: Staccato Six-Guns of Kristopher Spencer’s Film and Television Scores, 1950-1979