Okay, you can relax. Given arguably the best book of the series to work from, new director Alfonso Cuarón has turned out the best film to date, too.
Taking over from the cosily comfy Chris Columbus, Y Tu Mamá También helmer Cuarón creates a Potter movie that finally feels complete. The first two were scarred by Columbus' insistence on retaining a bit from every part of the book, his wide-eyed reverence resulting in a pair of adaptations that felt more like flickbooks of selected highlights than grown-up celluloid.
You can't accuse Cuarón of that. Bravely hacking the book back, he's sacrificed flashbacks and chunky exposition in order to streamline the core plot. There's a slight sense of loss (just who Moony, Padfoot, Wormtail and Prongs are is never explained, for example), but at least now the story slips smoothly along.
Cuarón's also brought stylistic coherence. Visually darker than previous installments, events mostly take place at night or under lowering clouds. He also introduces us to new areas of Hogwarts' grounds and brings every scene to life with a gliding camera here, a zoom there and a dynamic flourish everywhere. Even the string-heavy score does its bit, goosebumping around the action to create real unease.
Unavoidably, some problems still remain. Daniel Radcliffe, Rupert Grint and Emma Watson may look the part of Harry, Ron and Hermione, but only one of the three can actually bleedin' act. Radcliffe struggles when asked to convey any emotion more complex than a genial grin, while Grint's gormless mugging makes your eyeballs itch. If it wasn't for Watson, the scenes where the trio dominate the screen would be twitching agony.
To be fair, though, Cuarón does draw fine work from the grown-ups (Emma Thompson's Professor Trelawney being the painful exception). For starters, Michael Gambon does a good job of succeeding Richard Harris as Dumbledore, suggesting he'll make the role his own once he settles on an accent. Gary Oldman, meanwhile, fizzes in his few scenes as the escapee, Sirius Black, and David Thewlis' lugubrious Defence Against The Dark Arts teacher scuttles away with the film.
Yet it's the atmosphere and spectacle, the magic and the spine chills, that you most remember. Cuarón really delivers, spiking the twisty-turny plot with shuddery set-pieces: Harry taking to the skies on the back of Buckbeak, a CG hippogriff (the clue's in the name); a blustery, storm-soaked Quidditch match (our hero's broom turning to ice as he flies higher and higher); and a surreal, spookily beautiful face-off with a pack of swirling Dementors.
No doubt about it, the Potter franchise has just been magicked into life.
Watch the trailer
The Hogwarts report card shows some real improvement, though Radcliffe and Grint could do better. Roll on Harry Potter 4...