While the spaceship-creation mini-game has been dropped, you still access new worlds via a Gummi ship on a star map, landing on a new world to push the story forward. New worlds open up as old ones are cleared, in much the same way as Super Mario Galaxy 2, and while each has its own unique name, it's usually obvious to which Disney property the title refers; Snow White and the Seven Dwarfs' world is rendered as Dwarf Woodlands, for example.
However, as in the previous games in the series, Square Enix struggles to integrate its characters with the Disney mythology in a meaningful way. Too often it feels as though the Kingdom Hearts narrative has been squeezed into the gaps of the familiar Disney fairytales, seldom adding anything to the scenario, and often taking away from the economy of the original films. Witness Terra, attempting to comfort Cinderella, her dress in tatters, tearful at being prevented from going to the ball, assuring her that in moments of adversity, we must be careful not to open our hearts to darkness. Seconds later, the familiar plump figure of the fairy godmother arrives to drive the story forward where Square Enix's awkward character could not.
Because the classic Disney films are so efficiently constructed, the only points at which Square Enix can add their own characters and stories are in the previously unseen lines that link the drama together. So, when you arrive at the palace with Cinderella, your job is to escort her through dull corridors lined with shadowy ethereal foes en route to the prince, an unlikely journey, but just about the only place the developers could prise apart the Cinderella narrative in order to add their own imprint. When the princess is finally delivered into the waiting arms of her prince, your job is to rush to the top of the palace to defeat a boss character which, presumably if left to its own devices, would have brought the whole tale to a premature end.
Occasionally, your character will enter the Disney story not as a superfluous spectator, but as a stand-in for an established supporting character in the fable. In Snow White, for example, Terra assumes the role of the huntsman, charged with bringing back the heart of the princess to prove her death to her evil stepmother. Both approaches fall short of their potential, either coming across as an awkward, unnecessary addition or an ill-fitting mash-up of two surprisingly dissimilar sets of characters.
As with the other Kingdom Hearts games, some of this can be forgiven by virtue of the exemplary 3D modelling, animation and voice acting, all of which buoy Birth By Sleep in its weaker moments. In particular, the Disney cast is rendered with unrivalled expertise, the voice actors delivering their lines in pleasingly close approximations of the films.
That said, Birth By Sleep, originally developed as a PlayStation 2 title, does struggle to fill its lovingly rendered environments with much detail. Too often, you'll be presented with a deserted film set with rudimentary puzzles and platforming opportunities but none of the hustle and bustle of NPCs that would bring the scene to life.
The result is a mixed success. Developments to the battle system ensure that this is the most enjoyable Kingdom Hearts title in terms of its raw systems, but the storytelling and structure fail to delight in the same way. There's undoubtedly a great deal of craftsmanship on view, from the broad sweep of the cut-scenes to the minutiae of the character customisation. But the game falls short of the excellence promised by its component parts and enviable heritage - and it will do nothing to expand the Kingdom Hearts audience in the way its doting parent companies are no doubt hoping.