I can not say that this is a criticism, so I say that is just an opinion (as a fan) of the new film in the series, Harry Potter and the Half-Blood Prince.
Frankly, the movie was not what I expected, and that many other fans of the series also expected, as I walked by reading the forums on topic. I can not say of course not like the movie, after all we are talking about Harry Potter, but it was not my favorite, which was and remains "Harry Potter and the Chamber of Secrets." One of the reasons why I did not like much of "Harry Potter and the Half-Blood Prince" film was the simple fact that they cut things that I, as fan of the series, thought important for the understanding of history. There has not given to understand, but it happens that those who do not read the books probably do not understand very well what will happen in Part 1 of the latter for example.
But any way, errors (or not) aside, this movie was very funny and romantic too. Especially in scenes of Rony and the Mclaggen.