Just saw the movie. I guess I originally intended on explaining why it failed so much for me, but instead, I'd like to at least talk about its rare shining moments:
Severus Snape: It's always a treat to see Alan Rickman masterfully act out my favorite Harry Potter character, but this movie is basically about him, so it was extra nice. He went through a lot of rough moments, and if only due to his seriousness, he was also the source of chaos and hilarity. I heart him with every fiber of my being. :D
Draco Malfoy: Again, as opposed to the other movies, Draco is a HUGE character, basically the driving plotline, you know, other than memories and stuff. Contrary to my own opinions of the extent of his talent, Tom Felton did an AMAZING job portraying the many layers of Draco's problems and personality. I really felt for the kid.
Helena Bonham Carter: OK, so she was in the movie for ten minutes tops, but her little bits at the beginning and end of the movie were wonderfully creepy. What can I say? This chick knows how to be evil. She's everything I ever pictured Bellatrix Lestrange to be, only better. If only she had a bigger role...
That being said, the movie completely ruined many other aspects of the novel, not the least of which was the point. Though there are two major plots, the title of the book sort of gives away what should be the focus of the movie. Of course, in the long run, the other one is just as important, but SNAPE (AKA the half blood prince for those of you who haven't picked up the HP books, shame on you) is supposed to be delved into, so that his loyalty and the role he plays in the war is ready to be questioned in the epic last installment of the series.
They did not do their jobs with this. Not that I blame Rickman. No. I could never blame him, but I could blame the director, the producers, and the screenwriters (fail to all of you). All the ways they fail:
1) When Harry nearly kills Draco, Snape doesn't freak out. In the book he's supposed to realize that Harry has his old potions textbook right away, make him go get his textbooks, and THAT'S where Harry is supposed to hide it. Instead, Snape simply slides past Harry, calmly begins to heal Malfoy, and Harry BOLTS. No repercussions for almost killing a fellow student. His friends convince Harry to hide the book in the room of requirement (incidentally where the VERY IMPORTANT DIADEM ISN'T) and Ginny kisses him there, after very seductively telling him to "close your eyes."
2) Harry doesn't question Snape's loyalty enough. Sure, he mentions it to Lupin, Tonks, and Mr. Weasley (in the scene that NEVER HAPPENED IN THE BOOK. Yeah, they just made it up and sucked away valuable plot time) but he never goes directly to Dumbledore. This should have been a huge thing.
3) In the end, after Dumbledore's death, (ok whole other rant but there was no huge fight in the castle) when Harry chases after Snape, and (this is supposed to be epic) calls him a coward, Snape simply turns around. Harry continues to throw spells, Snape continues to deflect them, until Harry tries to use Sectumsempra on him. THEN, knocking Harry to the ground with a casual flick of his wand, he apathetically says, "You dare use my own spells against me?" (Camera shot to Harry's sort-of surprised face) then Snape says "Yes. I am the half blood prince." Then he walks away. Let me repeat this. He WALKS AWAY. That's it. He's supposed to blow up, because Snape has been protecting Harry all these years, working as a double agent and risking his very life repeatedly all to atone for the responsibili... wait. I'll explain that in a minute. But Snape should have been pissed. Really pissed. He doesn't like being called a coward.
4) They never mentioned that Snape was the person who relayed Trelawney's fateful vision to the Dark Lord himself. UM, PROBLEM. This is the driving force for Harry's misplaced anger and hatred toward Snape. It's what sets every fan's trust in the character spinning, grasping on straws, wondering if Snape is, in fact, evil. Of course, that particular mistake is the entire Reason Snape is a double agent, protecting Harry, risking his life to defy the darkest wizard of all time. Because he accidentally betrayed Lily (Harry's mom), the only person he's ever loved. How are they going to explain that in the seventh movie? It makes no sense, and it won't be easy to explain. Basically, by fucking up the background so thoroughly in this movie, they are in a pickle if they want to create halfway decent seventh (and eighth) movies.
Other things that were missing that I really really hated:
1) The absence of the rest of the Weasleys. Still no Charlie. Or Bill. Which also means...
2) No relationship stuff between Bill and Fleur. Yet they still plan on having the wedding scene in the seventh movie???
3) No fight at the end of the movie- the death eaters just sort of walk out. Where are the people?
4) No Trelawney. Stupid.
5) No Tonks/Lupin love.
6) No awkward wonderful Dursley scene where Dumbledore picks Harry up.
7) No Dumbledore funeral. (MAJOR PROBLEM)
8) No major Snape outbursts. I know. I already mentioned that, but really!
9) Ron... They wrote him out of the best friend role and replaced him with Hermione. Most of the time he just sat around smiling like a dumbass.
10) Nonverbal magic. I know, I'm getting picky, but you never got to see Snape teach DADA (defense against the dark arts)
11) ALL the other memories pertaining to the other Horcruxes. Come on, people. Harry would NEVER have found them if he didn't even get told what they were. Again, making the seventh movie harder to do correctly. Not that I ever thought they planned on doing it correctly...
12) The entire first chapter of the book... "The Other Minister" Granted, they showed a lot of the stuff described in the conversation, but I felt they should have mentioned Fudge was sacked... something they failed to do. Surprise.
Things they added into the movie that made me go "WTF?"
1) Quidditch. Ok, so I like quidditch, but it was BARELY in the book. It took up precious background story time.
2) Christmas attack on the Burrow. It never happened. It didn't lead to anything in the movie. Basically it was unnecessary fluff. Fail.
3) Harry hitting on an older woman. Right in the beginning. Fail #2
4) Ok, this was actually a good WTF, but they showed Draco's progress with the plans that he was assigned.
5) The last line of the movie: "I never realized this, but this place is really beautiful." UM Harry, I hate to break it to you, but your last father figure in life was just murdered before your very eyes. WHY prey tell, are you making bland observations about the scenery?
Things they kept that made me happy:
1) The birds. Hermione gets all emotional and makes a bunch of charmed birds attack Ron, and it was awesome to see it.
2) Someone call Ron "WON WON" in a lovey dovey voice. So awesome.
3) Memories. They didn't show all of them, but seeing Riddle grow up was eerie.
4) Snape. Any scene with Snape. No, I'm not in love with him, just slightly obsessed.
5) R.A.B. I'll leave that to the fans :D
6) Felix Felecis...
7) Aragog, his funeral and the drunken search for Slughorn's memory. Yes.
8) Fawkes' song. Almost cried. Didn't.
9) Slughorn. I mean, I knew they weren't going to cut him, but it was still amazing to see him, especially as an armchair, haha.
10) Draco. His presence in the movie saved it. I promise.
Actors that made me cry (not in a good way):
1) Rupert Grint: Not his fault, and good comic relief, but for GOD'S SAKE MAN, he's supposed to be more like Harry's best friend, less like a red-headed prop.
2) Michael Gamdon: (Dumbledore) Um. This fellow hasn't even read the books. He doesn't exude calm, seem wise, or do anything remotely like his character. Just because he's a successful actor doesn't mean he gets to look down at this role. Fail, Gamdon.
3) Radcliffe (Harry Potter himself): This boy needs to work on looking afraid, surprised, sad... basically he could rehearse every emotion in a mirror or something, because man, it just wasn't there. Nothing.
I know, this post was very critical of a lot of professionals. They put a lot of work into this movie, but in my opinion it wasn't enough. Not that I didn't enjoy watching it, but the problem was there was this empty feeling once the credits started rolling... like the obsessed fan deep inside of me (ok, maybe not so deep) knew that the movie had fallen short. And I know, it's a movie, only BASED on the book, but they are butchering the plot. Part of the appeal of HP is that it's not a typical formulaic YA novel. The story is intricate, detailed, twisting every which way, so that it all falls beautifully together at the end.
That'll be impossible to do with the movies, and I think it could have been.
Here's to hoping the inevitable remakes will do a better job. Even without Alan Rickman.