This film changed the way cinema would think of sequels and the idea of "film series". Before George Lucas created the franchise of Star Wars and popularized continuous film sequels, Coppola was putting out a follow-up and continuation to an amazing trip of a film. Not only do we learn more about the Corleone families' past, but we watch the parallel story lines of father and son coincide in their respective growths as characters. Screenplay wise, this script is a masterpiece and serves as a template for how flashbacks and parallel character developments can be used.