The film's Voldemort becomes a sad and silly caricature

What did they do to Voldemort?

I mean, honestly, what were Stephen Kloves and David Yates thinking when they decided to rewrite Voldemort for the final film (Harry Potter and the Deathly Hallows, Part 2, in case you forgot)?

First, they decide that the destruction of each Horcrux must affect him, either physically or psychologically. Not only is this contrary to J.K. Rowling's original novels, it's also contrary to their own earlier movies.

When Dumbledore destroyed the ring between films five and six, we see no evidence it had any impact on the Dark Lord. When Ron smashes the locket in Part 1, Voldemort doesn't howl in pain (either physical or psychic).

So it's not even internally consistent in the films that the destruction of Hufflepuff's Cup and Ravenclaw's Diadem would somehow damage Voldemort. And yet, there he is, damaged. Weakened, enraged.

This leads to the second, and even more significant, problem I have with the rewriting of Voldemort in Part 2. Instead of being a controlled, imposing, absolutely and resolutely sane villain as he is in the novels, Voldemort of the films degenerates into a giggling psycho.

Remember Hannibal Lecter in The Silence of the Lambs? We feared him because he appeared so sane, so in control, so intelligent and charming and well-spoken, and yet he was capable of such monstrous evil.

That's the Voldemort J.K. created in her novels.

In Part 2, however, he loses that mystique. In the scene where he leads his army to the front doors of Hogwarts to show the school's defenders the apparently dead Harry, Voldemort prances and giggles like the worst version of Batman's enemy, the Joker. He's no longer scary but silly.

Worse, Voldemort's silliness fundamentally changes his encounter with Neville Longbottom. When Neville steps forward in the novel, Voldemort recognises in him all the characterstics he, the Dark Lord, admires: courage, loyalty, purity of blood. Voldemort speaks to Neville with a tone of respect and says he will make a fine Death Eater.

This makes Neville's continued resistance, his resolute commitment to Harry and the cause, even more significant. Neville has spent his life trying to prove himself, to himself, to his grandmother, to the wizarding world. Harry Potter's cause seems to be lost and here is the apparent new ruler of the magical world, extending an invitation to him to join the new regime, to take a respected place in that world. And Neville refuses. His loyalty, his commitment to all things good, make him reject the very acceptance and recognition that he has long hoped for, even if that rejection will likely cost him his life.

In the film version, Voldemort sneers at Neville, treats him with disdain, makes fun of him. This new silly, giggling villain is so lost he can no longer even recognise in others the qualities he has long claimed to admire and respect.

The film's depiction of this scene is, unfortunately, an insult not just to Neville but to Voldemort himself. It's too bad. Kloves and Yates don't seem to have the artistic sensitivity to recognise the elegant subtlety and depth of J.K. Rowling's original novels and the final film in this epic series suffers greatly as a result.