The Thing Beneath the Bed was a great fairy tale turned on its head, switching the roles of the protagonist and the antagonist, and making the thing beneath the bed the least of your concerns. It managed to tell a traditional fairy tale, with each ending giving you a little bit more of the story, and with each ending making it more and more disturbing. It worked remarkably well, partly because it went places you didn't expect (though if you go back and look more closely at the illustrations, you'll find a handful of clues), enough so that I wondered if a sequel would work at all. We already know that the Princess is the real danger; what could mix us up this time around?
The answer is a baby brother. The Princess doesn't really like him, but like Labyrinth, when the goblins come to take him away, big sister winds up going to look for him. This time around, the story plays with us by using the Princess' menace as part of the story. We know there's an underlying vein of violence within her, and the authors use that to their advantage. The thing is, the story never really reaches a point where we're taken by surprise like we were in the first book.
The book maintains the structure of having multiple endings, each one setting a different mood (though, this time around, instead of going from happy to dark, we go from dark to happy), but the big reveal/surprise didn't pack as much of a punch. Part of that is because I didn't see any hints that suggested something like that would happen, but another part of it is that it makes the Princess a bit more sympathetic. And she shouldn't be. Not after the way the first book ended.
The book was cute, sidestepping the scenes of the Princess' violence to show the aftermath (which isn't to say that it wasn't still disturbing), and like the first book, the artwork matched the story perfectly. I just hope that Rothfuss and Taylor decide against telling any more stories involving the Princess. Once you get past the final ending of the first book, you really have all the story you need.