'HARRY Potter and the Chamber of Secrets" proves that sometimes you can have too much of a good thing.Crammed full of labyrinthine plot twists, this second installment will delight Potter-crazy kids even as their parents grow restless at the 2-hour-and-41-minute running time -9 minutes longer than the first film, which wasn't exactly sprightly.

It is also darker, scarier and more special effects-driven - and only marginally less violent than the PG-13 "Lord of the Rings," whose older-skewing audience director Chris Columbus and the producers evidently covet.

In other words, it's this series' equivalent to "Indiana Jones and the Temple of Doom."

Harry (Daniel Radcliffe) and his pals Ron Weasley (Rupert Grint) and Hermoine Granger (Emma Watson) are back at Hogwarts for a second term, and all heck is breaking loose.

Messages are being written in blood on the walls, a cat is hanged and students are being "petrified" by a mysterious monster from a hidden chamber whose entrance has never been discovered.

Suspicion falls on Harry, who may be descended from a long-ago wizard seduced by the dark side - shades of "Star Wars" - as well as on his nemesis Draco (Tom Felton), who has been promoted to seeker on his house's Quidditch team.

Or is the creature-loving half-giant Hagrid (Robby Coltrane) responsible?

To get to the answer, you have to get past an endless Quidditch match and involved special-effects sequences centering around flying cars, a massive snake, an animated diary, a ghost named Moaning Myrtle and a cave full of giant spiders.

"What was the point of sending us in there?" Ron asks after the latter episode.

Some grown-up Muggles will be asking the same question.

On the plus side, the three young leads are more assured in their roles, even if the boys' voices have dropped an octave or so.

Richard Harris, who died last month, has more to do as kindly Headmaster Dumbledore, though he looks alarmingly frail and his once-mighty voice is reduced to a hoarse whisper.

There are lots of new characters besides returning stalwarts like Professor McGonagall (Maggie Smith) - and most of them don't really add anything but length.

Kenneth Branagh has way too much footage as Gilderoy Lockhart, the new, egotistical Defense Against the Dark Arts teacher.

Branagh out-hams even Alan Rickman's Professor Snape, not to mention newcomer Jason Isaacs ("The Patriot") as Draco's slimy, Muggle-hating dad.

But they're benign compared to Dobby the House Elf, who rivals Jar Jar Binks as a computer-generated annoyance.

Screenwriter Steve Kloves still seems overly dedicated to cramming in every detail of J.K. Rowling's novel - while tacking on a schmaltzy Hollywood ending.

While Kloves will be back, the pedestrian Columbus has thankfully given up the directing reins for the next installment, "Harry Potter and the Prisoner of Azkaban," which isn't due until the summer of 2004.

Alfonso Cuaron, who directed the wonderful "A Little Princess," as well as one of this year's best movies ("Y Tu Mama Tambien"), seems likely to provide Harry with the sort of cinema magic that's in such short supply in "Harry Potter and the Chamber of Secrets."