Kali is one of my favorite goddesses, though I've never really worked up the courage to draw her. You've done a great job capturing the busy, layered feel of Hindu art with the various elements and implements you've incorporated here. I particularly like the snake holding Kali's hair up, it's a detail that is cheeky and dangerous all at the same time!
i like what you have going. the only thing i would have done differently, is spread the hands out a little bit more. it looks a little to cramped on the upper part. spread the lower hands out a bit more. other than that it is great!