Try as I might, I can't shake the suspicion that these films are too obviously built for purpose and too lacking in wit, warmth and humanity to survive much beyond the moment.
The thunder before the lightning; the rumble on the tracks... Passable and occasionally potent, but a towering great tease that has no right to exist in isolation from the latter - better - part of the story.
The penultimate instalment in the Harry Potter franchise is the scariest yet - but a film of real poignancy.
Your appetite will be whetted for what promises to be an almighty showdown before the curtain comes down on Harry Potter for good.
The tension never fades amid desperate chases, frantic escapes, titanic battles, noble deaths, electrifying encounters and enough humour to break the tension every now and again.
The first and third acts are over-busy; the middle one moves like an arthritic house-elf. Still, a decent smattering of magic moments and tension’s pumped up sky-high. Bring on Part 2.
I can see why J. K. Rowling regards this as her favourite film of the series so far. It may not be the most lucid or entertaining of her yarns, but her three leads have matured into genuinely interesting characters.
It’s just slightly disappointing that, with the momentum having been established so effectively, we now have to wait until next year to enjoy the rest of the ride.
Partly because it is building towards the finale, Harry Potter And The Deathly Hallows Part One shapes up as one of stronger offerings in the series.
This is less a movie than an appetiser before the main course next summer.
The pace is slow – even, surely, for addicts – except when things whoosh into life a little with the special effects.
What we have here is an uneven movie that is at turns touching, exciting and tedious. Ultimately it’s a movie that gives a distinct sense that maybe there isn’t enough content to justify it being split into two parts after all.
There is a good 90-minute story visible inside this highly decorated circus elephant of a film.
The end is nigh, but the penultimate Harry Potter adventure is a highly creative and lively affair, if lacking the genuinely scary moments it requires.
It feels like the longest, deathliest panto ever made – and still it isn't over.
As if to compensate for the longueurs, Yates delivers a few outstanding sequences.
Still, if its total success can only be properly measured upon arrival of the conclusion in July, the fact that Part 1 makes that worth waiting for should be taken as some kind of victory.
On the evidence of this penultimate film, the teenage wizard is getting the send-off he deserves. Roll on the summer.
It's overlong, padded out and, to one unacquainted with the novel, incoherent.
All we get is one-half of one-seventh of the series. No wonder it's unsatisfying.
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Interview with David Yates and Daniel Radcliffe
The world premiere
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Harry Potter and the Deathly Hallows
My children think the magic will last forever
How Harry Potter brought millions to Britain through the magic of film
Harry Potter: The end of the series is like a farewell to childhood
Wizard job: the end of the line for Harry Potter
The Harry Potter dividend
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End-of-term report: young Potter did more right than wrong
School's out: life must go on for Hogwarts graduates
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When J.K. Rowling thought Harry Potter sales of 30,000 were 'phenomenal'
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J.K. Rowling: 'if done right, Harry Potter could make a great film'
Is Harry Potter and the Deathly Hallows too scary for young children?
General release. Check local listings for show times.