Adults, according to most fairy tales, have stopped believing in magic. The people at Traveller's Tales probably haven't, though. And why should they? Just five years ago the developer saw an unlikely potion brewed from two fantastically powerful ingredients - LEGO and Star Wars - turn a faintly clunky platformer into an instantly charming mega-hit, and recent forays into Gotham City and the knockabout sandboxes of Indiana Jones have only continued the spectacular run.
With Harry Potter up next, you could almost forgive the team for doing little more than a quick palette swap before hiring the diggers necessary to tidy up the piles of money that are inevitably headed their way. But as we're hurtled through a quick hands-off demo of the latest game at a suitably Wizardy location in central London - there's plenty of wood panelling, ushers decked out in school robes and, rather worryingly, real owls - it's obvious that, while LEGO Potter is hardly a revolution, the designers have certainly spent the last few years hard at work, sounding out the peculiar strengths of JK Rowling's books and seeing how they can tailor their own formulas to mesh with hers.
Mostly, Traveller's Tales has been looking at Hogwarts. A familiar ramble of stonework and tapestries, stained-glass, shifting staircases and talking portraits, in LEGO Potter the venerable old pile is not just a simple hub. It's the heart and soul of the game, in much the same way as it is with the novels: a place that will change while the teenage wizard grows, gradually unlocking its secrets as the adventure progresses.
It's been created with typical class: sunlight slants through windows, beds in the dorm rooms are ripe for bouncing on, and everywhere you look there are pots of LEGO flowers to destroy for studs, or promising stacks of bricks gently spasming on the floor, calling out for investigation. The latest LEGO game may be unusually focused on a single location, but it's the series' biggest area yet, and its busiest too, filled with endless distractions and little gags.
LEGO Potter isn't turning into a Metroidvania, however. Most of the story levels will still work a little bit like instances - we're shown a bustling Diagon Alley complete with Gringott's Bank and The Leaky Cauldron, while the village of Hogsmeade is mentioned as a later location - but Hogwarts is intricately tied in with another of the game's new ideas: character progression.
Far more than a simple interactive menu, the school is the place where Harry and friends will attend lessons, learning new kinds of spells, which will in turn open up more of the story. Starting the game - which, as the title suggests, charts the narratives of the first four books - with no knowledge of magic whatsoever, by the end of the adventure, Harry will have filled up a reassuringly spacious selection wheel of powers.
We're shown a handful of the early spells. A lightning bolt attack works much like Star Wars' blasters do, sending out a puff of energy that knocks LEGO to pieces, possibly with slightly sharper auto-targeting than series veterans might be used to. Wingardium Leviosa works much like the Force powers, too, allowing the player to interact with objects, turning those flapping piles of bricks into quirky pieces of LEGO machinery, or even letting you fling irritating NPCs out of the way.
If it's starting to sound a little lazy, there are a few surprises in store. The LEGO physics model has been reworked - characters now send blocks skidding along the floor while they wade through them, and exploding scenery scatters in a more satisfying manner. At the crux of the recalibration, however, is the new "magical building" system, which gives the player the chance to use the levitation spell to move certain bricks about as they wish, rearranging and experimenting with them at will.
Coupled with the Crystal Skull's separate builder mode, it's one of the first few occasions in which a LEGO game actually tries to capture the feel of playing with LEGO. Inevitably, however, it has to be fairly tightly controlled, and the opportunity for freeform building will mainly be popping up for specific puzzles - such as constructing a wall to get to a selection of studs at the top - rather than being available for use in any situation. Seeing as wider implementation's tempting but probably game-breaking, it seems like a wise restraint, and if it's the genuine joys of construction you're after, there's always the forthcoming LEGO MMO. Or, you know, actual LEGO.
Finally, we're shown flight, handled in a typically no-nonsense manner, with the left stick controlling horizontal movement, while the jump button takes care of height. Like magical building, your broomstick use will be fairly strictly rationed, but with nice large arenas and plenty of clever touches - switching characters between Harry and Hermione will see your skills seriously impeded as you're placed in the hands of a weaker flier - it's a lot more interesting than another trip on a reskinned Snowspeeder.
With four books' worth of plot to wade through, over a hundred characters to unlock and thousands of colourful things to investigate, smash, and generally mess around with, Traveller's Tales is clearly onto another huge hit. Its template might be a little too familiar to pass as genuine magic any more, but at its heart this looks like another competent and witty outing: a near-bottomless pit of collectables for OCD children, and a pitch-perfect exercise in global branding.
LEGO Harry Potter: Years 1-4 is due out for multiple formats in May.