First of all, the title is no typo or mistake; this film, like Matrix: Reloaded, simply cannot stand on its own as a separate piece. There is barely anything I could call climax or closure at the end, it just sort of stops. I hate it when filmmakers do this; hey Mr. Yates, I think people would still come back for more even if you treated your movie like a movie, and not a mini-series. Oh well...
Anyway, forgive me if I ramble, as I'd like to talk as much about the film as my personal reactions to it and the HP plot in general.
The movie was well done, acting included on all fronts. I could take the main characters seriously in their new, much more drama-ridden environment. It was actually this movie where I finally glimpsed the great chemistry that developed between these three actors during the years: it is what enables them to smooth the rough edges in their performance and generally makes the whole thing better. Even Rupert Grint, who might never get an Oscar for best acting, was helped tremendously by it, and managed to do his part quite enjoyably as Ron.
The plot was, well, hard to follow at times. That being said, I had mainly the same problems with it which I had with the original book, namely that there isn't any consistent pacing anywhere. Perhaps Rowling missed her usual handholds with the school year, I don't know, but the story does not really develop; instead, "stuff happens" to Harry and co., then more stuff happens, and in the end the whole thing culminates at the battle at Hogwarts, but wait, how did we get there again?
I'm exaggerating here, of course. Actually, the subplots of the Deathly Hallows and especially the backstory of Albus Dumbledore are done really well (the latter apparently got the axe in the film for now, although I can't really blame the creators as it's a very difficult thing to translate to the movie format). The problem is more along the lines of the main characters hardly advancing the story at times; instead, they are often led by seemingly chance events - without them, I got the impression that they might have spent the whole school year camping.
Anyway, back to the movie. As I mentioned above, some story elements were regrettably (although often understandably) missing, but there was at least one thing which I feel was portrayed better, or at least more enjoyably (to me), than it was in the book: the Harry/Hermione angle. Make no mistake, I'm not a Harry/Hermione shipper. While I've read the books, I'm more or less absent from the HP fandom, so I only vaguely knew that it's a major pairing there; my actual couple preferences were neutral regarding Ron and Hermione, although I hope you won't find it disturbing when I say that I had the feeling Harry/Ginny might go somewhere as early as book two. ;P (Which did not make it any less random when it actually happened.)
So, despite not being some die-hard fan of the pairing, I can now see where the shippers are coming from, and I must applaud the film for not changing the eventual outcome (obviously), but showing that the possibility was truly there. Why? Two reasons: One, I feel it is more realistic this way, and two, it gives Ron a real reason to be jealous, instead of simply being a whiner. (He should have known better anyway of course, but let's cut the guy some slack here.)
"Realistic??" an outraged voice might say. (Oh my, I'm hearing voices now, not good. :P) "But Harry and Hermione are just friends, there never was anything between them!" ...Ahm, yeah right. That's exactly the realism I'm talking about: If you grow up with a girl in such a friendship, when the two of you are as close as they were, there is no way in hell the thought wouldn't ever cross your mind. These three friends have very different attitudes and dynamics regarding each other, but now I feel convinced that should it had been up to only them alone (without outside factors such as Ginny, etc. etc.) it could have gone either way. But it had to go one way or the other, and Rowling did not leave us any doubts in the book about the way she wanted it to go - making her work a bit more simplistic than the movie was in this regard, at least in my opinion.
(Random note: The Harry/Hermione kiss illusion-scene was as disturbing as it needed to be. It had been a long time since I've been more disturbed seeing two people kissing. It was brilliantly upsetting.)
EDIT: In a shocking turn of events, I just read part of an interview with Rowling where she in fact said something very similar about this portion of the book. Let me quote that, actually:
"[Kloves] felt a certain pulll between them at that point. And I think he's right. There are moments when [Harry and Hermione] touch, which are charged moments (...) Now the fact is that Hermione shares moments with Harry that Ron will never be able to participate in. He walked out. She shared something very instense with Harry."
I knew she had the films under relatively tight control, but I could have sworn that this was the director's own little conspiracy. I guess I was probably wrong then. Wow. O_O
It's sure going to be a long wait until July. ;)