Quite different to Godfather, and arguably even more brilliant – although I think both movies are among the best ever made, so that's splitting hairs.
Won the Best Picture Oscar and Robert DeNiro also won for Best Supporting Actor as Vito Corleone, the only time that two actors have won Academy Awards for the same role (Marlon Brando won a Best Actor playing Don Vito in The Godfather).
DeNiro is undeniably flawless as the Italian speaking young Vito Corleone, but it's Pacino's performance as Michael that's the key for me with these movies.
Unlike more recent acting roles he never overplays it, and moves convincingly from likeable war hero at the beginning of The Godfather to a bleak, powerful and merciless Don by the end of Godfather 2.
The pain and vulnerability shown only accentuate his growing power and control, chillingly and subtly portrayed by Pacino – in probably his best ever performance. You understand Michael and how he has become what he is.
The story takes place in two time periods – the 1950s as Michael runs the Corleone family operations, expands his power and struggles to keep his family together; and 1901–1925, showing Vito Corleone arriving in America and his subsequent rise to power within the underworld of organized crime.
These run concurrently with each other, providing a comparison between father and son. Although Michael appears to be in some ways more powerful than his father, ultimately he is weaker – and we see him destroying the family Vito created at the same time as we watch it's creation and growth via the flashbacks to Vito's story.
Brilliant storytelling, some of the best acting you'll ever see (including Robert Duvall, John Cazale & Lee Strasberg in strong supporting roles), and top notch cinematography.
Just see it. And Godfather 1.