Don't sell yourself short! I think this would be a good entry for the open category. I like your use of lighting and tones, and the composition is spot on. The only criticism I have is that your mid ground could use some detail, but awesome job nonetheless.

This is a very intricate piece and well done, however I do see a small amount of error with your proportions and I am not sure whether you meant the rough sketchy look or not. But really cool work nonetheless, good job.