The trailers advertised the new Harry Potter film as even more exciting, mysterious, and humorous than the first five. An eight-month release delay built up the hype even more. But as with many heavily marketed and highly anticipated movies, “Harry Potter and the Half-Blood Prince” fell flat. Not only did it not meet fans' high expectations, but it is by far the weakest installment of the series.

The film takes too many liberties with the book, removing significant events – the darker parts of the story – and relegating them to a very thin subplot, instead focusing on endless teenage angst and shenanigans. While this fluff is entertaining, it adds nothing to the overall series. And it is not just that the movie is mostly about the students' relationships; these romances are underdeveloped and for the most part so unlike the book that they are ridiculous and awkward.

Although the acting is superb, the script does not work to the actors' advantage. Familiar characters such as Hagrid, Snape, and Lupin have little screen time, while others – Draco Malfoy and Luna Lovegood – appear flat. Harry, the great hero, the Chosen One, is portrayed as a coward who does not even try to stop the plot against Dumbledore.

The all-important Horcruxes are barely explained. The mystery of the titular half-blood prince is glossed over in a sentence. And even after Harry learns important information concerning Voldemort and his past, he does not share it with Ron and Hermione, so for the first time in the film series, his best friends play extremely ­insignificant roles.

The cinematography is one of the few strong points of the film; there is a visually stunning shot of Harry and Dumbledore standing on a rock jutting up from the crashing ocean as they are about to enter the great cave. From that scene on, everything is suddenly serious and urgent, leaving the viewer feeling empty and cheated out of a pivotal film that could have served both to reveal secrets of the past and set up the epic series' finale.

With the upcoming two-part “Harry Potter and the Deathly Hallows,” director David Yates has two more chances to correct the tone of the Potter films and bring the series back to quality.