Apple is correct, and I would add that many great books and movies purposefully leave you guessing and wondering. The author of the play "Doubt" which is now playing on Broadway suggests that the final act of the play is supposed to take place when the members of the audience disperse and go to dinner or whatever to discuss what they just saw. More to the point is Kafka's The Castle, which literally ends in mid sentence. The bottom line is GFIII, while not a horrible movie by any stretch, is not necessary to the telling of the Corleone saga.