Well, since I started, I might as well go all the way, so I watched The Godfather part II.
I knew even less about it than the first one, so everything was new. It's impressive to go more than 40 years without spoilers, imagine my surprise in recognizing a young Robert De Niro playing young Vito Corleone! so the character has been played both by Brando and De Niro? wild.
The Vito storyline was great, they recreated old Italy and old NY very well. For the record, the italian / sicilian accents and dialects were so heavy that I had to watch the subtitles anyway
Michael was shown to be once again effective and ruthless, and both movies ended with him orchestrating multiple deaths but it was less triumphant than the first one - in the first, the killings marked his rise to power, in this one, they were just the last loose ends cut after his personal turmoil with his life (the wife getting an abortion) and his run-in with justice.
I've seen the two storylines described as the parallelism between the rise of Vito and the fall of Michael, but even though I might have grossly misinterpreted the ending, I don't see Michael in such a ruin, he's still running his empire, he "just" lost his marriage and a brother to it, but it's not that he's going to jail or be irrelevant. in the organization....