one of the review i liked and helpful

Rating: 8/10 (6 June 2015)

This must rank as the best film (along with part 2)of all time.An ensemble performance that has no weak spot.
Particularly, John Cazale ( Fredo) and Richard Castellano ( Clemenza) give wonderfully understated performances. You just have to believe that Castellano WAS Clemenza, he brings a real touch to his role.
John Cazale brings the troubled Fredo to life, and you can see the weak Fredo desperately trying to live up to the family reputation but knowing that he can never be what his father wants.
The story of one man's reluctance to be drawn into the murky family business,and his gradual change through circumstance, paints a vivid picture of this violent period of US history.
Do not miss this film!