I've just returned from watching the Half Blood Prince, and it was a mess. I don't know what they were playing at, but I've never seen a worse Potter movie. The linear plot is suffocating. While the movie begins with somewhat of a bang, the rest of it proceeds at some enforced speed limit, leaving no climatic or anti-climatic moments. In addition some of the key characters are missing or have such restricted roles that is it disgusting to watch ( the Dursleys, Neville Longbottom ). In addition Harry actually seems to be supporting the Ministry. The lack of Rufus Scrimgeour even prevents him from being Dumbledore's man through-and-through. Ron Weasley is made somewhat of a tag-along for the Harry-Hermione pair. It seems they were trying to put forth the idea of a Harry-Hermione pair, but that is ruined by the obvious Harry-Ginny romance throughout the movie. The only point where Ron does something is to play Quidditch.
Speaking of Quidditch, if you expected a nice match like the first three movies, you will instead be treated to the 7 Great Saves of Ronald Weasley.
Darkness is indeed rising, but that does not mean that the Order of the Phoenix do nothing while Death Eaters abound. It was somewhat of a joke to see Arthur, Tonks and Lupin running (yes!), when Harry and Ginny are trapped by the Death Eaters. But wait a minute, what is Bellatrix doing at the Burrow, and how does it just burn down. Wasn't it given the most protection by the Ministry of Magic?
It was also surprising to see the absence of the Order and Dumbledore's army at the Lightning Struck Tower ( or Dumbledore's tower as in the movie ). Meanwhile Harry stands around like some idiot while the Death Eaters and Dumbledore have a chat.
The Half Blood Prince was essentially meant to explain Voldemort's past, the story of the Gaunts, and hints to the Deathly Hallows. All of this is pushed aside and replaced by two tiny memories of the orphanage and Horace Slughorn. The ring has no mention of the Peverell coat of arms, nor physically nor in speaking.
If deviations from the book are not enough, David Yates failure to capture key moments was particularly visible. The kissing scene is just pathetic, the fear in the Wizarding world seems to be totally absent and the whole lake scene was just too lame. There is no palpable sense of magic about the cave ( quartz isn't magical you know ), nothing special in the potion ( it looks like water ) and the return to Hogwarts is far too easy. Dumbledore's death is very very underplayed. There is no dead silence, no grief in any of the characters except for a few unnatural tears.
Overall every scene seems to have some kind of half-heartedness in its execution. The only thing the movie has going for it is the comedy and some of the romance. The fixation with feet is also a bit annoying. Who the hell ties their boyfriend's shoelaces? Since the previous movie Hogwarts seems to have become just another Muggle school, with robes hardly ever being worn. I think that HBP will only do well because it is riding on the success of the earlier movies. But do not expect book fans to come out satisfied. This is the only Potter movie which doesn't leave you with a sense of magic when you get out of the theater. I don't know how it has received brilliant pre-release reviews but apparently the reviewers seem to have seen the movie as some disconnected one of a kind event, but it fails to capture Harry Potter, the story as well as the phenomenon.