Aside from a few minor book/movie differences that only a hard-core H.P. fanatic would notice, it was true to J.K. Rowling's novel. Smart move, breaking it into two parts. They were able to fit more in. They should have done the same with... gosh, with all of them. Then again, I guess the kids would be geriatric by the end if they dragged it out too long. As it was, it was tough to pretend Harry (Daniel Radcliff) was only seventeen.
My dear husband and I brought our nine-year-old daughters. No, they weren't scared. They know the story, having read the entire series and of course seen all the previous films. And if you haven't read the book yet, be warned that this movie does not have a happy ending. Save that for Deathly Hallows II.
SPOILER ALERT... Kinda
Now for my fanatical nits. Wahh!!!!
These aren't exactly spoilers if you've read the book, because then you know the plot. These are just things they didn't put into the movie. (Warning: This part is super boring unless you're VERY hard core.)
They cut out the touching scene when the Dursleys leave and Dudley is actually concerned for Harry. The Dursleys just sort of leave unceremoniously not even under any protection. The girls and I loved that scene. Dudley showed signs of having a heart.
Hedwig was flying around trying to protect Harry as they fought Voldemort and the Death Eaters in the air. Harry says she's what gave him away as the real Harry. In the book, Hedwig was in her cage and each fake Harry had a fake Hedwig. Harry was given away by his use of his trademark "EXPELIAMUS" spell.
Tonks (they always dress her so cute!) was supposed to be totally completely broken up about Mad-Eye Moody's death. I know, they can't spend time on grief, but he's one of my favorite characters and I sobbed my eyes out when I read that scene in the book. Also, Bill and Remus are supposed to search for Moody's body. That didn't happen. Later, at the Ministry, Harry does find Moody's magical eye, but he doesn't pluck it from Umbridge's door (so he can give it a proper buriel), as he does in the book.
Ron didn't dress up the ghoul in the attic to look like him. (I just realized that was missing.)
We didn't see Dean Thomas and Griphook in the forest.
We didn't get to see Luna's bedroom and the portraits of Harry and the others. How hard could that have been to do? I mean, come on, there wasn't one Harry Potter fan girl who would let you film her bedroom? LOL
There was no erumpent horn aka crumple-horned snorkack at the Luna house and the departing moment was changed a bit. (I won't totally spoil it for you.)
Oh, one other thing I can think of off the top of my head- Remember at the ruins of the Potter house there stood a memorial plaque that wizards and witches had signed. They didn't have that in the movie. Too bad. I would've liked to have seen it. It was touching when Harry read the notes people wrote him, not even knowing he'd one day read them.
There ya go. I am sure I missed some missing moments, but that's my first impression. We did love it, even my husband who isn't a huge Potter fan. He's seen the films but hasn't read the books, so he didn't miss anything I've mentioned.
ANOTHER SPOILER ALERT for anyone who hasn't read the book or seen the movie, but good info if you're bringing your kids:
The violence was your average Potter violence. Voldemort is scary looking. People curse each other. To me, the most disturbing part of the movie is the most disturbing part of the book. The Muggle studies teacher is hanging suspended over the Malfoy dining room table and is finally killed with the killing curse and Voldemort's snake is sent to eat it. (Thankfully we don't have to watch that part.)
The closest we got to a sex scene was when Ron's going to destroy the locket and he sees a vision of Harry and Hermione in an embrace. The vision is smoky from the chest down, but it appears they may be naked. But the image is created by evil in order to upset him. He knows it and we know it and he does the right thing and destroys the locket.