Now, usually in my lexicon "fun" and "creepy" don't have a high overlap. I've never been a big fan of horror movies, for example. Yet I do like reading both New Weird and dark fantasy as subgenres, so clearly this isn't a profound impediment to my ability to enjoy literature.
Flewlling's book is fantasy of the "hidden prince" theme, except with some pretty strange twists. She's not afraid to go to the most darkly logical corners of the arc her plot and characters follow. That's part of the fun. The sheer, bizarre creepiness that infuses this book borders on the delightful, and raises The Bone Doll's Twin above the usual mark of such fantasies. Not to mention the seeping dread that infused the story.
This was a fun read. I'm going to be seeking out the next two books in her Tamir trilogy to see how it all comes out.