Meu Irmão é Filho Único

This film is a dilemma for me. The first half just bounced along. The music was perfect. The energy pulled me along with it, seeing what felt to me like real people's insight into the serious subject matter. Interesting subject matter, interesting characters with motivation, who I cared about. You do laugh at things, even when serious stuff is going on most of the time. I didn't think it could get any better.

And then in a blink of an eye (about an hour in, maybe), it all went to pieces. It dawdled slowly through clichés. I felt like I knew what was coming, and I didn't even care. It was implausible, and at times boring enough for me to lose concentration.

Part of the problem is that it is (as another reviewer noted) about 20 minutes too long. How come are there film directors - talented ones - who haven't yet noticed that 90 minutes is generally enough? 8/10 for the brilliant first half.