I noticed in the credits this is based on a novel and that does not surprise me. It is perfect novel material - a span of a life over 40 years, meditations on the past, how that relates to the present.
There are lots of issues of male friendship and betrayal - which I love. Sadly these days most US movies are obsessed with female friendships thanks to the MeToo movement. IMHO boyhood male friendships are way more interesting as the whole status issue is so much more vital. Because boys and men HAVE to achieve to get status - if not, they get no respect from men but esp women. That often means money and wealth, career success, and is why boys are motivated to do crime, as here.
Naples is a very poor Italian city and has featured in several films and TV drama series. It offers a necessary correction to the often-romanticised view of Italy, from all the metropolitan elite, the cafe culture and food etc. Yes but there is also the religion, politics, corruption, crime and dire poverty (no benefit culture in Italy; no such thing as housing benefit etc). This is also international with issues of migration from Africa and Islam - the main character has been away 40 years and now lives a good life with a young pretty wife and a seafront apartment in Cairo.
Sure this is slow-moving, but stick with it - I could see the third act events coming (NO SPOILERS) and it was tense waiting for the inevitable.
Ultimate a very moving, even sad, story and film - about how boyhood friendship so often leads to, and is maybe based on, betrayal. It's a thoughtful film which stays long in the memory - for me anyway.
4 stars