We find Harry and his friend Ron Weasley descending the shifting Grand Staircase, running past portraits that provide shortcuts to other parts of Hogwarts’ vast grounds. (Once you learn the password for a portrait, you can use it any time.) They’re following the ghost Nearly Headless Nick, who can be summoned any time you need help finding a location around the school. We fall in behind the trio.

“The games have changed quite a bit during the series to match the age of the characters and the situations they find themselves in,” explains Bunney. “The early games were definitely for younger kids with traditional videogame mechanics such as jumping onto platforms, but the most recent games are much closer to the look and feel of the films.”

Tryouts. Ginny Weasley tests the mettle of a would-be Gryffindor Quidditch keeper.

He adds: “We use the movie set blueprints, scan the actors’ faces, and record their voices, so now you play as Daniel Radcliffe as Harry Potter. In fact, this year the filmmakers have referenced our 3D Hogwarts for planning shots, since we’ve had to build all the connecting bridges and corridors they don’t have.”

“Everything we do is approved by [J.K. Rowling], so we and our players know it’s real.”

- Jonathan Bunney, executive producer

Authentic, Explosive, and Disgusting

Harry and Ron arrive at their destination: the potions class taught by professor Horace Slughorn, who retired but returned at headmaster Albus Dumbledor’s behest. Slughorn plays a key role in the game’s story, while potion-making has evolved into an important mini-game this time around, thanks to Harry’s discovery of an annotated textbook — marked as once belonging to the Half-Blood Prince — that helps him perfect the skill. “We spent a lot of time on allowing you to make many authentic, explosive, and disgusting potions in multiple locations around the school,” says Bunney.

Trapped! Harry and a fellow Gryffindor Quidditch player find their way blocked, but he knows a few spells that will free them.

We watch as Harry races against the clock to complete a complex potion that will earn him a special luck potion known as Felix Felicis. (Yes, it will play a vital role later in the story.) He must carefully add each ingredient to a simmering cauldron, waiting until it turns just the right color — if he pours in too much, smoke billows from the concoction, forcing him to clear the air before he can continue. Some steps require him to increase the flame below the mixture to obtain a new hue, or to shake ingredients before adding them. Neatness counts in the overall score, and it turns out to be trickier than it looks to add ingredients without making a mess.

Lost? Don’t Lose Your Head. Harry and Ron summon Nearly Headless Nick to help them find their way around Hogwarts.

Of Quidditch and Dueling

Harry succeeds, of course, and soon potions class ends. Bunney and I follow Harry to Quidditch practice, where he is now Gryffindor team captain and its seeker, a position whose only role is to catch the Golden Snitch and end the game. As you control Harry’s flight around the field, you must pass through a series of stars to get closer to the Snitch — miss too many of them and you’ll fail, requiring you to start over.

As we watch Harry soar through the sky on his broomstick, Bunney explains: “With Professor Umbridge out of the picture, the Quidditch season can start again, so we’ve brought it back.

“We use the movie set blueprints, scan the actors’ faces, and record their voices, so now you play as Daniel Radcliffe as Harry Potter.”

- Jonathan Bunney, executive producer

It delivers not only lots of action and excitement, but it also frames some of the developing relationships between key characters.” Umbridge, in her villainous Harry Potter and the Order of the Phoenix role, banned Harry and Ron from playing the sport.

Now that the two boys can participate once more, Harry makes Ron the Gryffindor keeper, despite Ron’s mediocre skills, which increases tension on the team. Meanwhile, Ron’s new romantic entanglements only serve to make him more nervous during Quidditch matches. (To learn more, see “The Leads”.)

Dueling has also returned for The Half-Blood Prince, and Bunney and I later take in a meeting where Harry and Ron battle with their wands for the right to represent Gryffindor’s dueling club. You can now move around while dueling, allowing you to dodge your opponent’s spells while launching some of your own. You won’t have much trouble defeating Ron, as Bunney and I observe, but more intense matches against members of other Hogwarts houses await. (You can also join the flying and potions clubs, letting you practice those skills any time.)

Two Wizards Enter, One Wizard Leaves. Harry and Ron battle for the right to represent Gryffindor in dueling club.

“We’ve rebuilt wizard dueling to make the controls tighter, more fun, and more powerful,” Bunney remarks. “We’re allowing players to see what it would be like to take part in a series of competitions that J.K. Rowling only briefly covers, but everything we do is approved by her, so we and our players know it’s real.”

Amazing Access

As Harry and Ron run off in search of further adventures, Bunney and I take a seat in the large hall where the duel took place. Other Gryffindor students mill around, full of excited chatter about the dueling club, and the subject turns to Rowling’s participation in the game’s development. “We send her scripts very early on and get her feedback,” Bunney explains.

Wing of Bat, Eye of Newt. Potion-mixing requires a quick pace but a deft touch.

He continues: “It’s almost always positive — because we love the fiction — and always constructive. For example, she might recommend that we use a different character because a line or situation may be more fitting for them. And since the movie studio is only about an hour away from the game studio, we get amazing access to their work and regularly share our work with them.”

Bunney concludes: “We’ve been pretty adamant about telling the story of the Half-Blood Prince. Our game is not just based on a movie script, but also on a 600-page book that is full of wonderful detail that can generate amazingly fun gameplay, so we make the most of it by ensuring that everything allows you to directly engage in a part of the storyline. By the end of the game, you should be able to tell me the story of ‘The Half-Blood Prince,’ whether or not you’ve seen the movie or read the book.”

If you liked this game, check out:

• A Vampyre Story
• Ankh
• Ankh II: Heart of Osiris
• Jack Keane
• Harry Potter and the Sorcerer’s Stone
• Harry Potter and the Chamber of Secrets
• Harry Potter and the Order of the Phoenix
• The Incredibles: Rise of the Underminer
• Pirates of the Caribbean Online
• Shrek 2
• Spider-Man 2