Really good watch, could watch again, and can recommend.
This is surprisingly dark, and underrated. While the animated characters are almost grosteque in their stylization, it serves fairly well when it comes to the undead. It also pushes the boundaries of it being a "kid's" movie or an "adult's" movie in it's content. So this is probably a movie for "older younger" audiences.
Not only is this a great concept, effect execution, and story, the characters that do pop, really do. I honestly could have done without a few of them, but most of the important characters work for what they need to do.
There is a much appreciated "twist" that examples some self-aware story telling that comes with the tropes typically involved with "I see dead people" stories. Its really rather refreshing without removing the idea that burning witches at the stake was an atrocity in history.
The story is touching and charming and just requires an open mind, which is part of the message of the story.