In “Caligula: The Ultimate Cut,” absolute power corrupts absolutely, but even using absolutely all of the footage shot for the notorious production back in 1976 does not necessarily result in a better film. The most expensive independent film ever produced until that time, “Caligula” was conceived by late Penthouse founder Bob Guccione as a sexually explicit film that also featured real actors and high production values; hiring bestselling author Gore Vidal to write a script for Italian avant-garde director Tinto Brass (“Salon Kitty”), Guccione subsequently attracted such respected thespians as Malcolm McDowell, Peter O’Toole, John Gielgud and Helen Mirren to star. But after disputes between Brass and Vidal prompted the author to sue to remove his name from the film, Guccione commandeered final cut and inserted shots of graphic sex and violence, prompting cast and crew alike to disavow the film.

Devoting a substantial portion of his adult life to “Caligula...