The characters in the movie are complex.

I couldn't agree more!

Wow, a people-eating dust bunny who's sole purpose is to carry out the girl's bidding, good or evil. That's unsettling. The dust bunny may have no sense of right or wrong but does the girl? But then she's 10.

Now I see what you mean by "the darkest Grimm story". I like that there's symbolism. It's something I always look for in movies because at the very least, I want to learn something new or unusual at the end of each day, even if its from a movie. Your review has piqued my interest. Nicely done.