Seeing as how I didn't much like the book, I guess it shouldn't be a surprise I didn't like the movie much either. The cinematography, special effects, acting...all great in my opinion, I just don't like the story- or lack thereof, rather. The only part of the story I liked was the stuff about Snape, which is also one of the only chapters of the book I liked.
Some of the things I never liked are more forgivable in movie form, I suppose, since there's time restrictions, such as
Lupin's death for instance. In the books it was a huge slap in the face to have such an important character (As well as Moody, who is supposed to be the most powerful auror around) have off-screen deaths. They did the same thing with Fred in the movie...hell, I don't think they even mentioned which twin it was that died in the dialogue. It was basically just Harry looking over, going, "oh shit, they're dead" and then they move on.
All the same plot holes that were present in the book are actually back, and they actually made them even more pronounced than they were in the book, which is something that blows my mind, especially
The part where Ron opens the Chamber of Secrets using parseltongue...it didn't make sense in the book and having them actually show it to you just drives the point home that much clearer- parseltongue is supposed to be a magical language that nobody can learn to speak, and all of a sudden you can? And to add to the absurdity, it's freaking Ron, he shouldn't be bright enough to come up with an idea this smart. Okay, being a bit sarcastic with that last one, but still!
One thing I am glad they removed though, was the Fiendfyre. It made no sense to me that Crabbe (Well, I guess in the movie it's Goyle), who was always a terrible student, all of sudden could conjure up magic that was so difficult that even Hermoine didn't dare to touch it- a simple solution that would've saved a ton of time in the first, incredibly boring camping section of the book had Hermoine bothered mentioning it, instead of wandering around like a bunch of idiots looking for Gryffindor's sword. It made more sense that if there was still that many Basilisk fangs hanging around, they would put them to use rather than just leaving the damn things in the Chamber.
Also very glad they removed that awful part where Harry successfully uses Crucio on Carrow, because apparently someone spitting at McGonnagal pisses him off more than someone killing the only person living he considered family.
Neville still doesn't get his showdown with Bellatrix, and many angry Nevillefans cried in anguish (Especially given that they bothered giving Neville that line in the fifth movie, "Better now that they're going to be avenged"). I think enough people have criticized the stupidity of Molly Weasley fighting Bellatrix that I don't need to elaborate on it.
Still, none of that still has anything on the Elder Wand crap. First, how did Draco own the Elder Wand? They say you need to defeat...or kill, they can't seem to decide which one it is, but either way, it doesn't make sense for Draco to have taken the wand ownership from Dumbledore, because disarming hardly counts as defeating, otherwise tons and tons of people have been "defeated" in the past, and it just becomes a total confusing mess. But even if you buy that, Harry never disarmed Draco...he plucked the damn wands from his hand when he wasn't looking- there was no magic involved- besides, that was Draco's wand, and not the Elder wand, unless you're going to say that disarming someone means you also get to own every single wand that person has ever owned. Let's say you buy that- how the hell did Voldemort die? We've seen people use other peoples' wands all the time without any ill effect (Aside from it being "not as effective"), but apparently only in this case it causes Avada Kedavra to rebound and kill Voldemort. They don't even bother explaining this the least bit in the movie, because they knew it made no sense.
Also the epilogue still sucks- you don't learn what happens to anybody, you just know they have a bunch of kids. What happened to Neville, Luna- did Harry ever achieve his dream of being an auror? None of these questions are answered.