I was about to complement this movie for hewing closer to the book than the previous two, but I started thinking about what was missing and now I’m mad again.
It completely glosses over the connections between Harry’s father, Lupin, Pettigrew, Black, and Snape. In fact, I don’t think they ever make the connection between them and their animagus aliases or how the Shrieking Shack became the Shrieking Shack, or who made the Marauder’s Map or why. That’s really important stuff for motivations between these characters, and it reveals a lot of Harry’s father’s history, which he knows absolutely nothing about.
The conflicts between Crookshanks and Scabbers, and the problems they cause for Hermione and Ron are mostly ignored. The deteriorating condition of Scabbers is gone. And then there’s the weird bonus scene where Harry chases Pettigrew with the Marauder’s Map. And all of the Quidditch stuff is dropped after Harry falls off of his broom in the game against Hufflepuff.
So just like the previous two movies, this one is still a mess. It makes changes that don’t make a lot of sense.
But something I forgot to complain about in the novel is that WIZARDS CAN MANIPULATE TIME. Holy hell, two thirteen year old wizards are given an artifact that lets them go back in time and permanently change the course of events for the rest of the story. They’re concerned about Sirius Black getting a hold of the Marauder’s Map because he could track Harry with it, but there are artifacts in this world that can manipulate time. Talk about messed up priorities.