And with supporting roles from the likes of Diane Keaton, Robert Duvall and Lee Strasberg, to say nothing of Roger Corman and Harry Dean Stanton in bit parts, this is nothing short of magisterial.
As the beginning of Part II echoes the opening of "The Godfather," so too does the end. Because of the manner in which circumstances are handled and considering the people involved, the impact here is more forceful. The tragic flaw has accomplished its poisonous, inevitable designs. Coppola punctuates both movies with a gut-twisting exclamation point.
Coppola is unable to draw all this together and make it work on the level of simple, absorbing narrative. The stunning text of "The Godfather" is replaced in Part II with prologues, epilogues, footnotes, and good intentions.
Three hours and 20 minutes of Al Pacino suffering openly, Robert Duvall suffering silently, Diane Keaton suffering noisily, and (every so often) Robert De Niro suffering good-naturedly is almost too much, but Francis Ford Coppola pulls it off in grand style.
Vincent CanbyThe New York Times
The only remarkable thing about Francis Ford Coppola's The Godfather, Part II is the insistent manner in which it recalls how much better his original film was...Even if Part II were a lot more cohesive, revealing, and exciting than it is, it probably would have run the risk of appearing to be the self-parody it now seems.