First of all, the special effects were a mess. I mean, animatronic owls? Really, guys? I remember the previous movies had state of the art computer generated graphics, and there was some of that in this one but other parts just looked cartoony. Some of it actually looked to me like hand drawn animation, which I thought did not mesh well with the rest of the movie.
A lot of the actors' English accents did not sound authentic. Some would drop in and out of different accents, others just spoke in a way that was nearly impossible to understand. The wands they used looked cheap, as if they were made out of plastic. They looked like toys you could buy at the store.
Many of the sets were very poor. The paint was cracked and honestly some of it looked like the kind of backdrops you would expect in a high school stage production, not a $200 million blockbuster. There were also a lot more house plants lying around than I think would be in a place like Hogwarts.
I was also thrown off by the giant monster truck rally that occurs in the middle of the movie. It completely derailed the story and felt very forced. The long shots of monster trucks loudly revving their engines really took me out of the world of magic and wonder that the filmmakers tried to create.
The product placement was crass and unsubtle. Ron Weasley never mentioned that he liked Mentos in any of the other movies, but in this one he seemed to take out mints every time he was on screen. He held the Mentos packaging in a way that was really unnatural and seemed to designed to get Mentos as close to the screen as possible.
Sometimes, in the middle of a scene, I got extremely frustrated because the camera would drift off away from the main action and just linger for a long time on staircases and other parts of the set. You could still hear the dialogue, but it was really difficult to follow what was going when you couldn't actually watch the actors perform their parts. Come on, that's like moviemaking 101 guys.
I thought it was very unnecessary to bring back Dumbledore after he died in the last movie (spoiler alert). But the way they decided to do it made it even worse. Portraying the deceased wizard as a brain in a vat was tasteless to say the least. Especially because the "brain in the vat" actually just looked like a lump of clay in a murky fish tank. The scenes where the characters just sat with Dumbledore's brain looking uncomfortable were not very dramatic. There was no dialogue, and the actors would enter and exit for seemingly no reason.
Denzel Washington seemed like an odd addition to the cast. I know he's a great actor, but his intensity seemed to frighten the children in the audience as well as many of the other actors in the many scenes he was in. I don't want to say affirmative action played a role in his unusual appearance in a movie of this kind, but I'm pretty sure affirmative action played a role in his unusual appearance in a movie of this kind.
All in all, it was a very poor experience from start to finish. Which reminds me, the movie was way too long. I remember the other movies were all well over two hours and I had no problem because they were adapted from very dense books that I have no intention of ever reading. But this one clocked in at nearly four hours, which I think is testing the limits of what's an acceptable running time for a children's movie. I actually left halfway through because I was bored and hungry. I made myself a ham sandwich and took a nap but when I woke up I remembered that I wanted to see the ending. So I went back to the theater to catch the last couple of scenes. When the credits rolled I realized why the movie was such a disaster. They had like twelve directors on this thing! Talk about too many cooks in the kitchen. Knowing that, the bizarre tonal shifts - like when a dramatic scene would suddenly turn comedic without warning - made a lot more sense. It's the worst movie I've seen since The Last Airbender (I know, I shouldn't say things I can't take back, but I'm not exaggerating when I tell you that it really came close to matching how bad The Last Airbender was).
Here's hoping Part II is better.
PS - Hermione was not naked in a single frame of this movie as far as I can tell. This was very annoying because I think that actress would look good naked and also I'm pretty sure there's only one movie left so they are running out of opportunities to have Hermione be naked for a few scenes. I know it's sort of a minor quibble considering the monumental raft of problems with the rest of the movie, but it's important to point out some of the obvious ways they could have redeemed the really shoddy work they did.