This movie is sort of like if Harry Potter was turned into a magical girl anime. The characters are charming and unique, and even in the short time you get to see them, you really get a feel for them. The animation and direction is just spectacular, fluid and expressive. The story is just perfect for the time they have to tell it, a simple premise that unfolds naturally, starting off small and unfolding into something epic.
Maybe my favorite part about all of it is that there's no 3D in it. All the backgrounds are hand/drawn, a look I've sorely missed as more and more studios start implementing 3D backgrounds. This doesn't mean the studio holds back at all when it comes to dynamic shots, either. They just suck it up and do it right.
If you want to watch it for yourself, you can find it on YouTube, from Trigger's official channel (in Japanese with English subtitles):