One of the inevitable realities of life is that Hollywood studios, with their play-it-safe attitudes about creativity and their need to maximize profits, often create "series" and "franchises" from movies that were never intended to be first chapters of anything.

Sometimes, as in the case of Paramount Pictures' The Godfather, Raiders of the Lost Ark or Star Trek: The Motion Picture, one successful movie can spin off two or more sequels that might vary in quality but are more or less still watchable.  (It helps, of course, if there is a plan to make more movies in the creators' minds, as was the...