All right, going over it again, here is a more detailed/in-depth critique.
Hinata's portion was a good way to start the fic, being gentler than the others and thus helping the reader get used to the fic's premise and structure before the real whammies start.
Choji's part was fine, nothing spectacular but a good, solid piece of writing that fits well with his character.
Tenten's ends a bit weakly, but is again fine.
Neji's part was good, again fitting well with his character and helping to emphasize that pre-exam Neji was more a good person with issues than a bad person who could be redeemed.
Shikamaru's part was interesting, a bit more of a stretch than previous sections but well-written enough to be convincing.
I said before how I feel about Naruto's section, and unfortunately rereading brings me no closer to explaining why.
Shino's section was very good, another piece that seems to fit very well with the character but at the same time going further into the character, if that makes sense. That was the first one that nearly made me cry.
Sakura's piece made so much sense.
Sasuke's part was good, and like Neji helped to make him seem less like a bad guy and more like someone whose intentions are fine but whose major issues are ruining their execution.
Kiba's section was excellent. This was the second one to bring me close to tears, and oddly enough it was the bit about how Shino talked and did not stop talking even though he normally hates unnecessary noise that really impacted me.
Ino's piece was another good one. I found the amount of swearing actually detracted from the impact, as the words distracted from the meaning behind the sentences, but that might be a personal quirk. The way it indirectly pointed out that Iwa ninja are just as human as Konoha ninja was, to me, the most emotional. This was the third section where I almost cried.
And Lee's section was simply brilliant. Writing the "springtime of youth" without mocking it or exaggerating it to parodic levels is very difficult for many fanfic writers, and you managed. This was the part that brought me closest to crying.
There you are. On a random note, one-third of the Konoha Twelve have names starting with S. If you discount Sasuke but replace him with Sai it still counts. This strikes me as odd. How did I only now notice this?