Darker again than its predecessors, and tighter, while also expanding on the ongoing story underlying the series. Over the course of this one and Azkaban, the films have assumed an increasingly epic feel - something I hadn't expected given that the main protagonists are children (more particularly, children who, apart from being able to do magic, aren't particularly preternaturally self-possessed or able to avoid the pitfalls of growing up), with events taking place within a relatively confined compass.
(Indeed, that notion of the end of childhood runs strongly through this one, with really the whole film serving as an extended metaphor for that particular passage - it's well done.)
