This looks very intriguing and well thought-out. Now, to explain why, let's get down to it!
Vision: Everything about this picture of art conveys emotion and mood. Excellent choice of color, excellent outlining. Four and-a-half stars. Originality: Since this was a commission you did for someone, I won't judge too high or too low in this category, but I will give my honest opinion: You made the commissioner very proud. Four stars. Technique: In all likelihood, the one thing that makes a drawing good is the effort, and you put forth a lot of it. Four stars. Impact: Critics such as myself will see a lot of worth in this. Four stars.
To conclude my critique, I'll say that you've done a great job doing this, and as long as you can maintain the current level of quality, you'll find your place in the art world.