For those of you who haven't been keeping up, the world is in dark days at the beginning of Deathly Hallows: Voldemort's followers have infiltrated every level of the wizarding world, from the British government to Hogwarts School of Witchcraft and Wizardry. The world lives in fear of attack, as the Death Eaters are looking to purge the world of everyone who is not of pure wizarding blood. Voldemort, however, has another goal: achieve ultimate victory by eliminating Harry Potter, the only one who can kill him. Harry, Ron, and Hermione, meanwhile, are out on a quest to destroy the six Horcruxs, objects in which Voldemort has hidden a piece of his soul magically. They'll have to destroy them all in order to defeat Voldemort once and for all, and they'll need to do so before Voldemort gets a hold of the Deathly Hallows, three objects that, when united, make the holder invincible to death.
There's two really important things to remember going into this movie, and they are essential to one's viewing pleasure. The first is a core principle that applies to all of the Harry Potter films: if you compare the movies to the books, you're bound to be disappointed. The films cannot incorporate everything from the books, especially after Goblet of Fire when the books reached mammoth sizes. One has to think of the film as its own entity, and treat it as such. That being said, compared to the other films, this one is probably the most faithful to the source material, a benefit of having the book split into two films (a decision that, inspired by money-grabbing greed or not, I believe is exceptionally beneficial from a creative standpoint).
The second thing that you have to keep in mind is that this is only part 1 of the story. Just like the first half of the book from which it is based, Part 1 is mostly set-up for the epic finale, which will arrive in Part 2. What that means is that Part 1 may be short on wall-to-wall action, but it is without a doubt the most nuanced, subtle, and mature Harry Potter film yet.
I want to emphasize that "mature" part. The films, like the books, have changed as Harry has grown up. The first two films were simple kid flicks, fascinated by magic with little in the way of complicated (or even interesting) storytelling. However, starting around Prisoner of Azkaban, things started getting darker, both thematically (moral ambiguity and flawed heroes begin to work their way into the story) and aesthetically (check out director Alfonso Cuaron's muted color palette in Azkaban, which would be recreated to various degrees in each subsequent movie). This film is the culmination of that maturity in many ways. The actors have played these characters for so long, that they could just repeat themselves. Instead, they continue to take them into surprisingly human (and terrific) territory.
There are two excellent moments that exemplify this. The first comes at the beginning of the film, barely a minute in. The trio are about to go on the run rather than return to school (where they'd be in grave danger), and Harry and Hermione are about to leave their respective homes for the final time. While Harry's departure from the Dursleys is cut short, it's Hermione's scene that's really amazing: she stands behind her parents, who are watching TV, and magically erases their memory of her. She disappears from their family pictures, her parents are completely oblivious, and the devastated look on her face is one of the series' most heartbreaking moments. It's something that couldn't have been done in any previous film.
The second moment is a beautiful little moment that comes later in the film, after (SPOILER ALERT) Ron has left the group in a jealous rage. Hermione is depressed and Harry, pulling her out of her chair to lead her in an impromptu dance. It's a moment that's not in the book, and it fits perfectly with the characters' development up to that point. It's sweet, heartwarming, and beautiful, a reminder of how powerful their friendship is.
The filmmaking has matured as well. Director David Yates, who's been with the series since Order of the Phoenix, has proven to be a great match for the series' darker years, bringing a great sense of levity to the films. With no Hogwarts in sight this time, the film gets an opportunity to explore the British countryside and the city of London, and the result are some excellent sequences, such as the ambush on the way to the Weasley's house, a tense infiltration of the Ministry of Magic, and a disorienting chase through the forest. First-time Potter cinematographer Eduardo Serra has created some absolutely gorgeous images, and the camera work he uses is refreshing for the nine-year-old series.
Of course, Potter fans know about author J.K. Rowling's ruthlessness in this book: every character is suspect to being killed. And the big deaths here will hit home hard for fans, myself included. So be warned, fans: it's brutal.
Overall, I found this to be the best Potter film so far, and a terrific film in general. Yes, maybe it's slow, and maybe there's not much payoff in THIS entry, but remember that it's all setup for Part 2.