10 Reasons The Harry Potter Movies Were A Massive Waste Of Potential

The changes discussed in the previous three points (Sirius' resolute death, the prophecy simplification and the refocusing of The Half-Blood Prince on Snape) all seem to have been made for the same reason; to keep the movies about Harry growing up and not get them bogged down in mythology. This makes the ending one of the oddest mis-steps in the whole series; it actively lessens the coming-of-age element of Harry's final victory.

OK, so in the books the final battle between Harry and Voldemort takes place in the Great Hall with everybody watching. Harry explains how, through the rules of wand possession, he's already won - Voldermort's wand belongs to him, so any attack is doomed to fail - but the Dark Lord fights him anyway. He's defeated when his own spell rebounds and (in J.K. Rowling's own words) "Tom Riddle hit the floor with a mundane finality, his body feeble and shrunken".

That how you write an ending: Harry ultimately defeats the villain with a mixture of his own innate smarts, lessons learnt from his experiences and support of his friends; he shows his maturity in front of all those he's grown up with by offing his enemy the chance to realise their mistake; and Voldemort is returned to his normal form, the mythical veil of He Who Shall Not Be Named removed immediately.

In the film you have the pair fighting by themselves in the courtyard, while everybody licks their wounds inside. It's a flashy showdown, with a bit of flying, bright whisps sparking everywhere and a desperate crawl for their wands that culminates in Voldemort evaporating into thousands of tiny pieces. It's only after this that Harry explains the manner by which he won, and it's done with none of the confidence evident in print.

Everything that made the book conclusion so satisfying is gone, replaced with whiz-bang theatrics, and do many of the previous changes made in the aid of focusing on Harry's journey are moot because they're not actually paid off.