I like the perspective. I think it's very dramatic and you seem to have done a good job with the shadows and things you say you're working on. (Although I'm probably not the best source to ask. I don't know much about drawing) The one thing that bugs me about the picture is that the ice bomb is very obviously a collection of copied snowflakes and circles. If you changed the size more, rotated them, or had some random blobs of magic energy, it would probably look more organic and natural, in my opinion.