Unfortunately, this movie was used solely to set up the plot for the final two movies, a fact that led to a lack of any real action or much forward movement. Choices were made (likely due to time) and scenes were left out that were some of the book's best, including the final battle at Hogwart's surrounding Dumbledore's ultimate death. For one of the most climactic scenes in the 7 books, this movie sped through it in a way that would have been laughable if it were not such an important oversight.
Hopefully the last 2 movies are out of this world spectacular, because the Half Blood Prince was thrown away in deference to them.