It flows. It gives you laughter, nostalgia, and understanding. It is moral in the sense that it conveys an apparent morality but also amoral because of the apologetic Bruno sequences. We know his character very well as from a relatable friend or acquaitance, and Roberto embodies us: our fears, our constant hesitation. Melodramatic ending or a necessary one?
I found it very enjoyable in the first part, then it dramatically slows down. The ending is quite strong, but I lost the very contact with the film a few minutes before and so I found it quite weak in its realization. But conceptually, seen from the side of the only character with a speaking soul, it is very powerful indeed.
The movie finally has become actual. Hordes of old farts and critics have spent their time complaining it was a prophetic movie for their generation and finally it has become true since a decade more or less. It must have been fun for them pushing younger people down the cliff at the end.
The "jolt" at the end might not have been the factor that Dino Risi claims to have made this film so successful. But it is indeed a jolt and, as abrupt as it is, turns a sardonic road film into a contemplative portrait of what has been painted thus far. Like Alexander Payne said: "All great films must be seen over and over".