The second Harry Potter film is better than the first, not because it is true to the book's story, but because it is true to the book's atmosphere.
The first Harry Potter movie was very good, but it stayed so close to the book that it spread itself too thin trying to get at every single detail. This adaptation of Joanne Rowling's second book (which I think is the weakest among the entire series) does indeed have all the good parts but focuses primarily on the main storyline. The film skips a lot of the background details, which makes for effective pacing, while taking liberties with the story to fit the big screen.
Here Harry Potter (Daniel Radcliff) and his friends, Ron (Rupert Grint) and Hermione (Emma Watson) once again encounter Voldemort (Christian Coulson) as a memory that has the power to become real. Voldemort opens the Chamber of Secrets freeing a fearsome Basilisk, an Alien-like snake that can kill with a glance. The snake's attacks threaten to close down Hogwarts School and Harry must stop them or be sent home to live with his foster parents (you can understand his motivation when you meet them at the introduction of every book/film).
The film is darker than the first, with scenes that are definitely creepy: Harry's encounter with a strange hand in Diagon Alley, Ron and Harry getting stuck in a willow tree that attacks them with its branches, Harry and Ron escaping from the giant spiders, and Harry's final battle with the Basilisk. There are also some Orwellian themes touched upon here, including Dobby the Elf's masochism and slavery, the ideal of some of the "Purebloods" to cleanse Hogwarts of the "Mudbloods".
The familiar high-profile cast do a fine job, with the newcomers, Kenneth Branagh as the pompous (and hilarious) new Dark Arts teacher Gilderoy Lockhart, and Jason Isaacs as an evil-oozing Lucius Malfoy, particularly standing out. While the child actors carry their roles well, some of them do tend to overact. The score does a great highlighting the suspense, which there exists a lot of.
The set design and accompanying cinematography and production deserves a paragraph of its own. The integration of computer generated images and the actors is very seamless. The Hogwarts school, the surrounding countryside, and the brief Quidditch match are all rendered with amazing reality.
If the first film was the setup, this one's definitely the payoff. Even though I know what happens next, I can't wait to see it.