Well, I've just come back from my second time watching the film and I think it's time for some random thoughts!
tl;dr: The first half of the film was stronger than the second. The writing of the adaptation was great, but the book's atmosphere remains in the book. And the acting was stupendous.
The Bad:
1. The camera work could have really been better. Steadier. Fewer distracting extreme close-ups, fewer super quick cuts and shakiness. Sometimes they contributed to the sense of disbelief, confusion, rush, etc., but for the most part it was distracting.
2. I don't know, I just never got the feeling of deep, abiding horror and wrongness that I got in the books. We didn't have Katniss watching the Reaping of other tributes, we had very little sense of the previous tributes of District 12 who had just vanished into the Capitol and died in front of the eyes of millions, and -- this fact really, really bothers me -- not a single tribute except for Katniss and Peeta had last names. Even when just announcing training scores and interviews it was "Marvel," "Rue," until it was the protagonists' turn, then they got full names. That annoys me deeply. Suzanne Collins herself was working on the movie, and even she couldn't be bothered to at least come up with full names? That plays havoc with my suspension of disbelief, especially because this film is clearly not told just from Katniss' POV. Either all of the tributes should have complete names, or all of them should be nothing but first names. The point is that from the beginning they're all equal, equally victimized by the Capitol.
2a. Damn I really want to somehow work out a crossover between The Hunger Games and either The Giver or Majora's Mask. The Games themselves are something that fits so perfectly into Majora's mindset that it must be done.
3. Basically, the first half of the movie (in District 12) was so much stronger than the second. Once they entered the Capitol, things felt less intense and meaningful. In the Arena the level of tension wasn't steady or steadily climbing. The transition from Arena back to Capitol was so awkwardly done.
3a. The muttations were much scarier in the books, where they showcased just how far the Capitol is willing to degrade and dehumanize its tributes.
4. I've set "Rue's Lullaby" to 1. a nameless tune from 'Paris, Je T'aime,' 2. Appalachian Spring, 3. Hush, Little Baby 4. The Ashokan Farewell, 5. A combination of The Ballad of the Goddess and Zelda's Lullaby. I'm reconciled to the film's tune (though not quite the exclusion of the chorus, which to me is the best part), but... I wish the tune in the film had had more heft to it, for lack of a better word. And that Rue's four-note call had found its way into the score.
The Good:
5. The acting. Jennifer Lawrence was a perfect Katniss; Josh Hutcherson made a very good Peeta to contrast her, and Rue's Amandla Ste(r)nberg (sp?) was the right combination of darling and daring -- endearing, but not cloying. In fact, the casting across the board was spot-on -- special mention goes to Prim, Effie, Foxface, and Clove -- I really liked Clove, the smallest Career but clearly deadly. The only odd people out were Gale (why did we start cutting back to District 12 only when romance started coming up? I would have liked to see Prim's reaction to any of the trials Katniss faced before then... oh, right, love triangle), and President Snow. He exuded a little too much Santa Claus to be scary. But I liked him all the same.
5a. Wes Bentley's Seneca Crane was a nice Mephistopholes. And oddly, slightly hot.
5b. Also, I miss my fat Falstaff!Haymitch. But Woody Harrelson was good, with the odd touch of Jack Sparrow in him. (I have never before wanted to ship Haymitch/Effie.)
6. CESAR FLICKERMAN IS MY FAVORITE PERSON IN THE WORLD. I think writing in his character, as a well-done Mr. Exposition, had the added bonus of providing some relief, if not humor. In the midst of all these very restrained, realistic performances, there's Stanley Tucci with blue hair and eyebrows hamming it up, subsisting entirely on a diet of chewed scenery.Being FUN.
7. The writing was enviable. The way that they compressed so much of the story into just what was needed, priorities set in the right place, such careful depiction of character, and really brilliant ways of showing rather than telling, but then telling when it was necessary. It's a superb adaptation, just in terms of the script. Were there things missing? Yes (like I said, reapings of the other tributes, more time with Rue, more time to be ambiguous with the budding Toast romance). But overall, commendable.
8. Small detail, but I liked how they built up a tiny rapport between Foxface and Katniss. Still wordless, but they had their moments. It's like, they wouldn't ally together -- they're each too suspicious and besides Foxface doesn't bear a striking resemblance to Primrose -- but in another time and place, they could have been friends. And THAT, my friends, is fanfic meat & drink.