The 2002 video game Harry Potter and the Chamber of Secrets was developed by KnownWonder for Windows and Mac and published by Electronic Arts. It is the sequel to Harry Potter and the Philosopher's Stone for PC and Mac. As its sequel, it has similar action-adventure platforming gameplay. The game was succeeded by Harry Potter and the Prisoner of Azkaban for the PC, which also has similar gameplay.
The only playable character in this version of the game is Harry Potter (voiced by Tom Attenborough), although in a certain part of the game he uses the Polyjuice Potion to disguise himself as Gregory Goyle.
- Ron Weasley (voiced by Greg Chillin), Harry's best friend, usually seen leading Harry to classes and challenges or to the Quidditch stadium, or in cut scenes.
- Hermione Granger (voiced by Emily Robison), Harry's other best friend, a brainy girl who also leads Harry to classes. She is petrified toward the end of the game.
- Ginny Weasley (voiced by Victoria Robinson), Ron's little sister, who Harry has to rescue at the end of the game.
- Fred and George Weasley (voiced by Lewis MacLeod), twins, older brothers of Ron and Ginny. They play as Beaters on the Gryffindor Quidditch team. They also set up the bean trading system seen throughout the school and grounds.
- Draco Malfoy (voiced by Lewis MacLeod), Harry's arch-rival. Harry duels him at the Duelling Club. He is also in the clips where Harry goes to Quidditich practise, and where Harry (in the figure of Goyle) is in the Slytherin Dungeon to talk with Draco. He can be seen at the House Point Ceremonies, and at the end of the year feast. When Harry plays Quidditch against Slytherin, Malfoy will be the seeker.
- Myrtle Warren (voiced by Victoria Robinson), a ghost who haunts the first-floor girls' bathroom.
- Albus Dumbledore (voiced by Lewis MacLeod), the Headmaster of Hogwarts. While normally absent from a good part of the game, he features prominently in a cut scene in which he tells Harry that he does not think that Harry is the Heir of Slytherin. He also appears at the end of each day to announce the latest house point totals, and at the end of the year ceremony.
- Professor Snape (voiced by Allan Corduner), the Potions master. Known for being unusually strict, he is usually to be found in the dungeons, near or in his classroom. If Harry gets caught in the Slytherin common room while sneaking out, Snape shows up and expels him, and Harry will have to try again.
- Professor McGonagall (voiced by Ève Karpf), the Transfiguration teacher. Her classroom is located on the left side of the second floor. She isn't seen very often because Harry doesn't have any Transfiguration classes. There is a time in between classes/challenges when the classroom has just been open when McGonagall is holding a class. If Harry enters the classroom, she will give him a warning and send him out. If Harry enters a second time, McGonagall will take 5 house points away. She also leads Harry to Dumbledore's study when Nearly Headless Nick has been petrified.
- Professor Flitwick (voiced by Allan Corduner), the Charms teacher. His classroom is located on the right side of the second floor.
- Mrs Norris: Argus Filch's cat and acts as the caretaker's assistant. She is petrified near the beginning of the game.
- Professor Lockhart (voiced by Mark Lowenthal), the Defence Against the Dark Arts teacher. His classroom is located on the third floor. He also is in charge of the Duelling Club, and accompanies Harry and Ron into the Chamber.
- Rubeus Hagrid (voiced by Jonathan Kydd), a very large half-man, half-giant, usually found in his cottage in the grounds. He can also be found right in front of the entrance if Harry goes outside just before Defence Against the Dark Arts.
- Aragog (voiced by Fred Ridgeway), An Acromantula that dwells in the Forbidden Forest.
- Professor Sprout (voiced by Ève Karpf), the Herbology teacher. She teaches in the greenhouses, which are located on the right-hand side of the grounds.
- Oliver Wood (voiced by Lewis MacLeod), Gryffindor Quidditch team Captain. Wood appears after Harry's first Defence Against the Dark Arts Class. Wood leads Harry to the Quidditch pitch, and re-teaches Harry how to play Quidditch.
- Percy Weasley (voiced by Lewis MacLeod), a Gryffindor prefect, older brother of Fred, George, Ron, and Ginny. Percy can be found in the Gryffindor Tower or the Duelling Club if Harry visits there in between classes/challenges.
- Peeves (voiced by Chris Crosby), a poltergeist Harry meets during the Skurge challenge. He also pops out of certain chests.
- Gregory Goyle (voiced by Harry Robinson), one of Malfoy's friends and his figure is playable when Harry transforms into him.
- Lee Jordan (voiced by Greg Chillin), the commentator for Quidditch and is good friends with Fred and George Weasley. He does not appear and only his voice is heard.
- Lucius Malfoy (voiced by Allan Corduner), the father of Draco. He is seen in Borgin and Burkes and then in Diagon Alley. He is also mentioned during Harry's Quidditch training. The last cutscene he appears in is the one where he fires Dumbledore and arrests Hagrid.
- Tom Riddle (voiced by Harry Robinson), the young version of Lord Voldemort. He is controlled by his diary. The diary is destroyed during the showdown in the Chamber of Secrets and Riddle is destroyed with it.
- Flipendo: "Knocks back" enemies and objects. Harry learned this spell in Philosopher's Stone.
- Alohomora: Unlocks locks, including those found on doors, chests and secret doors. Harry learned this spell in Philosopher's Stone.
- Lumos: Cast on Gargoyles, temporarily illuminates the caster's wand and reveals magically hidden things. Harry earned this spell in Philosopher's Stone.
- Skurge: Clears ectoplasm (an "unpleasant greenish substance left behind by certain ghostly beings") from doorways and off floors. Harry learns this spell in Charms.
- Expelliarmus: Available only in wizard duels. Deflects spells cast by the opponent.
- Diffindo: Severs ropes, spider webs, and plants, such as Venomous Tentaculas and Spiky Bushes. Harry learns this spell in Herbology.
- Mimblewimble: Available only in wizard duels. Prevents opponents from accurately casting their next spell.
- Rictusempra: Stuns magical creatures and reduces stamina in wizard duels. Harry learns this spell in his first Defence Against the Dark Arts lesson.
- Spongify: activates certain specially marked "Spongify" carpets and paved floor, making it bouncy, allowing Harry to leap high off of it. Harry learns this spell in his second Defence Against the Dark Arts lesson.
Behind the scenes
- In the previous computer game , there is a background character named Marilyn who is a Hufflepuff that collects curious objects. As an inside joke, in the next adaptation for Chamber of Secrets, there is another extra, Arthur, who is stated to be Marilyn's younger brother and shares her strange hobby.
- Colin Creevey and Justin Finch-Fletchley are omitted in this version of the game.
- In this version, Dobby only appears briefly in the initial cutscene, warning Harry not to go to Hogwarts and then disappearing.
- Ron states that the Ford Anglia is parked in Charing Cross Road. This is a real London street and the location in the Harry Potter universe of the Leaky Cauldron.
- There is a secret level known as the Gryffindor Challenge. It's only accessible through the debug mode, which is activated by pressing the Delete key next to the help key. To get to the challenge, one needs then to move to beyond the door usually leading into the Gryffindor Tower's dormitories, and deactivate the debug mod again. There are nine secrets, and ten challenge stars there. There is no timer for this level.
- Even if Slytherin had the most house points at the end of the year, they will still get second place.
- The basilisk is not green, but purple and it attacks by spraying a purple stream of venom which Harry must dodge. After failing to kill Harry from the mouth of Slytherin's statue, the snake pops from grating in the floor to try and bite or spray the young wizard. When it is killed, it simply falls on Riddle's diary, presumably burying its fangs in the book and destroying it.
- Neville Longbottom is not present in this version of the game, despite being present in the previous game.