Spoiler Alert. Don't read further if you don't wish to read spoilers.
Two words to describe Warner Brothers' adaptation of "Harry Potter and the Half-Blood Prince:" Disappointing and dissatisfying.
Best parts: Slugworth was brilliantly cast. Every scene with Malfoy in it is utterly fantastic. Tom Felton brings raw emotion to the fore. You're crying for him in the scene when he is sobbing by the bathrooms. All the humorous/cute interactions between Ron and Harry are great, too. And Luna is always amazing.
Worst parts: The two most climactic scenes were poorly done. Dumbledore is supposed to be sobbing out apologies to the sister he killed, and instead he says nary a word. It is also Dumbledore who freezes Harry in place so that he is immobile (which affords Harry a much better view for one). He doesn't just command him to stand there. There should have been a focus on the killing blast, on Dumbledore's toppling off the tower, the subsequent madness and confusion, a stronger duel between Harry and Snape...it just falls short of what that scene could have been. What happened to Snape declaring he wasn't truly a coward? What about the intensity of that scene? It all went to hell.