It's been a little over 2 weeks since I scoped out Harry Potter and the Deathly Hallows part 2 in London at the midnight debut. At the time I watched it, I had not read a single one of the books to avoid spoiling the movie experience. It's a simple but unescapable law that the book is always better than the movie -- assuming the book was written first and not as a novelization of the film.
Since I saw the film, I have blown through the first 3 books and am currently about 1/3 of the way through The Goblet of Fire. I'd still like to provide some comments about the last Harry Potter movie from the perspective of someone who hasn't read the series. All of the questions I had when watching the Deathly Hallows haven't been addressed so far in the books. It should go without saying but just in case:
I saw The Deathly Hallows part 2 at 12:01 am on Friday, 15 July, the first public showing. It was the second feature of a double-header that included The Deathly Hallows part 1 as the lead-in. I was quite thankful to re-watch the seventh film as many of the smaller details of the plot had been forgotten between the time I saw it in the winter and now. The two films, part 1 & 2, work well together as a long, single movie, not surprisingly since together they make up the plot of the final book. The only thing that would break-up the narrative flow is the fact that at the beginning of part 2 they show a brief recap of what happened at the end of part 1 -- namely Lord Voldemort robbing Dumbledore's grave to collect the Elder Wand and Harry mourning the death of Dobby. Part 2 resumes at the coast as Harry buries Dobby without the aid of magic and the group takes shelter in an old home by the sea to talk to the rescue Mr. Ollivander.
The 3D effects appeared to be solid in the film, at least at the beginning of the movie. I am both red-green colorblind and wear glasses so I have handicaps that usually interfere with the quality of 3D. Of course, being in 3D, the overall color of the film tended to darker. And towards the end of the film I stopped noticing 3D at all. Which I guess is a way of saying that it didn't feel gimmicky and didn't detract too much from the experience.
After breaking into Gringott's to destroy a horcrux stashed in Bellatrix Lestrange's and escaping on the back of a dragon, most of the last movie is devoted to the epic war between Lord Voldemort, his Death Eaters, and army versus the forces of good protecting Hogwarts. But the Gringott's scene did raise an issue. Harry disarms Bellatrix and takes her wand; Mr. Ollivander identifies it as such. Therefore Hermione disguised as Bellatrix has access to it when the goblins ask her to present the wand as identification to access the vault. Why they didn't use it rather than Harry casting the Imperius Curse. After discussing it with people who have read the books, it makes sense. However, rather than presenting details to create this gap in the plot, why not just not include the scene of Ollivander identifying the wand?
Just about every surviving wizard who's ever been featured in a Potter movie makes an appearence in the last battle. The special effects are stunning for all the different spells flying back and forth and the creatures summoned to do the bidding of the Dark Lord. The duel between Molly Weasley and Bellatrix, much hyped at the premiere of the movie, was neither as long nor as visually spectacularly as I had imagined. Nevertheless, it was satisfying to see insane Bellatrix finally be defeated.
Harry's confrontation with Voldemort in the clearing raised more questions. Major spoiler so if you haven't seen the movie or read the books, you should definitely skip the rest of this paragraph. Harry is a horcrux. I'm not exactly sure how it happened. I think when Lily sacrificed herself to protect the infant Harry, causing Voldemort's curse to rebound, somehow part of Voldemort got lodged in Harry and this somehow functions as a horcrux. I'm not sure. The books probably give more details.
Voldemort manages to kill Harry with the Elder Wand. In the death state, Harry meets Dumbledore in a pristine and white version of King's Cross station. He also sees a visual representation of the part of Voldemort in him that Voldemort has just killed. For some reason, Harry has the ability to chose whether or not to die here. I'm not exactly sure how he has this power; it's kind of left unexplained.
I thought it had something to do with the Deathly Hallows. Dumbledore has gifted Harry the Resurrection Stone which he used to recall his parents and godfather prior to confronting the Dark Lord. It's also revealed that Harry is the true master of the Elder Wand, not Voldemort, because Snape, whom Voldemort kills to take the Elder Wand from, was not truly its master. The Elder Wand belonged to Dumbledore and it was Draco Malfoy, not Snape, who defeated him because it was Draco who actually disarmed Dumbledore. Snape killed him after he had already lost the duel. (From what I understand, in the books it's explained that Snape could not take the wand from Dumbledore because they had colluded and thus Snape didn't really "kill" him.)
The big reveal, then, would be that the Invisibility Cloak that Harry has had since the first movie wasn't merely an Invisibility Cloak at all but rather The Cloak of Invisibility, the third Deathly Hallow. Having all 3 would make Harry the Master of Death, thus giving an explanation for how he has the power to choose not to die. But that's not the case. In the movie, we're just supposed to accept that he can choose even though Dumbledore has been keeping the secret that Voldemort must kill Harry in order to be able to die himself. If Harry could just choose to come back to life after Voldemort has killed him, why not disclose this information to Harry, or at least tell Snape so that he can pass it along with the last of his memories?
Back to the plot. After killing Potter, Narcissa Malfoy is told to verify that Harry is dead but she lies to the Dark Lord. Hagrid carries Harry's dead body back to Hogwarts, led by the Dark Lord who has come to gloat. He expects the wizards and witches to bow before him now that Harry, the only one who has ever and who could ever defeat him, is dead. Neville Longbottom, long the butt of jokes, gives a rousing speech defying the Dark Lord and then Harry springs to life. All hell breaks loose again as the Dark Lord chases Harry and the Death Eaters do battle.
Nagini, Voldemort's familiar, is the last surviving horcrux. Understanding that Harry is trying to kill Nagini, Voldemort keeps the boy at bay and sends Nagini to kill Ron and Hermione, who have finally kissed in the bowels of Hogwarts while retrieving a basilisk fang to destroy the last horcrux. Just before Nagini can strike, Neville swoops in to save the day, wielding Gryffindor's Sword and killing Nagini. Neville is finally a hero, too.
Without his immortality juju, Harry finally destroys Voldemort with the Elder Wand, which is rightfully his, after a flashy wand fight. The world is saved. And Harry decides to destroy the Elder Wand rather than letting it ever fall into anybody's hands again.
One other "spoiler" is that Severus Snape, rather than being a Death Eater, is revealed to actually have been working with Dumbledore in secret the whole time. Harry learns of these secret heroics from Snape's tears. Snape had loved Lily first and had been jealous when she chose James Potter instead of him. And even though Snape had been mean and nasty to Harry throughout Hogwarts, he had never wanted to kill the boy. Oh, and Snape and Lily have the same Patronus. I'm pretty sure it's Snape's Patronus that leads Harry to Gryffindor's Sword in the frozen pond.
The scene that has received the harshest criticism from people I know is the last one, where the heroes have all aged 19 years and are sending their kids of to Hogwarts. The aging makeup is regarded as being pretty poor even though it's supposed to be the same technology that made the Curious Case of Benjamin Button age in reverse so effectively. I was kind of upset to see Harry with Ginny. Come on, buddy, Cho Chang was so much cuter...
Overall, it's a really great ending to the series and a thrill-a-minute. It doesn't stand well on it's own because it's mostly just action with very little plot development. A fine capstone for the bildungsroman / hero's journey story of this generation.
I don't think I had quite the same experience seeing the last film and not just because I haven't read the books. For many people I've talked to, the remember starting to read the first Harry Potter when they were between 7-12 and they have grown up with the stories. The next book coming out was part of their youth and part of their experience. When the first book came out, I was almost 19 and just a month away from starting university. I was aware around the time the first movie came out and saw the first movie. It didn't motivate me to devour the books like some of my college peers. Not even a ringing endorsement from my professor Dr. Susan Napier in a class on anime roused my interest enough to read the books. I enjoyed the movies ok up until the Goblet of Fire, when I got bit by the Potter bug. But, citing the rule above (the books are always better than the movie), I held off on reading the books for SIX YEARS so that I could enjoy the films in their own right and on their own terms rather than comparing them unfavorably to the books.
Now, I'm zipping through the books and can't wait to get home and watch the movies all over again. They aren't the stories of my generation. I'm not sure there was this kind of global culturural phenomenon when I was 10. We watched GI Joe, Thundercats, and He-Man but nothing swept us up like Harry Potter has for this generation. Teenage Mutant Ninja Turtles was huge but it didn't drive millions and millions of kids to read hefty tomes. We just spent too much on chunks of plastic and got 1 good film out of the deal.
 Can anyone think of an example where this isn't true; e.g. the movie based on the book is actually better than the book? I've heard Jaws is that way but never read the book.