I think that after Vito Corleone died, it took all the life and, well, let's say "brightness" out of the family. Everytime I watch "Godfather 2", I find that I feel most happy when they flash back to the scenes in Sicily of young Vito. Michael is a great mob boss, but he seems so much darker than his father. That might probably go hand in hand with the way the movie was shot -- dark and gloomy.