The little-known art house film Harry Potter and the Sorcerer's Stone was bound to produce a sequel or seven. Luckily, the filmmakers had a ready source of material, thanks to obscure author J.K. Rowling, who kept additional novels secured in a shoebox where no one could ever read them.

Okay, not quite.

These films were box office beasts from the start, and Harry Potter and the Chamber of Secrets looked to continue the trend. Like she did with the first flick, Rowling stuck her nose where it belonged and made sure the filmmakers kept as close to the book as they could. But as Rowling's books got longer and holy-moly-that's-long-er, things were bound to change.

What's the Same

Director Chris Columbus bent over backwards to get all the details straight on this one. Harry (Daniel Radcliffe) returns to Hogwarts to face the mystery of the Chamber of Secrets, and all the action that goes down ends up making a difference down the road. That's why our explorer-director made sure to include plot points like the whole Tom-Riddle's-diary-is-a-horcrux fiasco and the scandalous Ginny-hearts-Harry drama.

And it's not just plot devices we're talking about; Rowling's bigger-picture themes and characterizations make their way into the movie, too. This lady wasn't a big fan of authority, apparently: the book takes plenty of digs at pompous teachers like Gilderoy Lockhart (Kenneth Branagh), a self-important blowhard whose magic skills are sub-par, to put it lightly. And sure enough, he shows up in the movie in full-bore nitwit mode, demonstrating perfectly how some teachers just don't know what they're talking about. (Not all—we promise.)

Rowling also delves into all those petty human evils like prejudice and misunderstanding. "Mudbloods," anyone? Malfoy (Tom Felton) throws that word at Hermione (Emma Watson) because he's a big jerk—in book and movie alike. By maintaining all that jazz in the movie, Chris Columbus has prevented the Wrath of Fandom from falling on him, his children, and his grandchildren.

What's Different

Like any movie adaptation of a giant-cockroach-crushing sized book, running time is of the essence. The book had the chance to slow down and explore all the cool corners of Hogwarts. (We want to go to there.) The movie, on the other hand, has to move things along, lest the non-Potter fans grow bored and start a riot in the lobby.

The result? Tons of scenes and subplots get cheerfully chucked under the bus. While it doesn't affect the main storyline or any of the primary themes, we're left with a less buttery and chocolatey chocolate chip cookie. Some examples: Peeves the troublemaking poltergeist is MIA, as are less important beasties like the gnomes in the Weasley's garden.

Speaking of everyone's favorite red-headed family (sorry, Jefferson), the Weasley's don't get as much screen time in the movie as they do in the book. Twins Fred and George basically act as walking scenery, and while little sister Ginny plays a key part in the plot, her freaky-deaky book version stuff is kicked to the curb. That means she seems to come out of nowhere at the end when Tom Riddle kidnaps her—kind of takes away the whole slow-build-up part of it.

Ginny's not alone in her movie snub. How about Dobby the Elf (voiced by Toby Jones)? This little guy tries to save our hero—and almost kills him—more than once, but we only get a sliver of the Dobby cake in the movie. We don't get to know Dobby's disturbing masochism quite as much, either. Though to be fair, we're not sure we want to see that on screen anyway.

Life at Hogwart's naturally loses out in the book-to-movie transition, too. Remember the dueling scene? Well, the movie focuses on Harry and Malfoy, instead of showing us the whole range of duel-fightin' kids. School dances, class sessions, and other mundane events (Hogwart's mundane, that is) also get left behind. Bottom line: so much goes down in the book that flavor and atmosphere sometimes have to get passed up in favor of story, story, story.

But wait—there's one last thing. Most of the Harry Potter films don't even dare to add material to the already thick-as-a-brick book they're based on, but Chamber of Secrets makes an exception. You might remember that the final battle with the Basilisk is pretty concise in the book. In the movie, though? Not so much. Columbus spices it up with a boatload of whiz-bang special effects. And it's probably a good call, since, you know, the people want action.

So people, Shmoopers, acclaimed movie-critics: what did you think? Shmoop amongst yourselves.