Okay first time i'm doing a critique
I love the technique you used. It has many possibilities to what they are saying in this picture. The impact is really quite good. The originality is also good. I love the background.
My only bad points:
I think Shadow's hair has not been exaggurated enough. His hair is a little more wild that what you drew it like, as seen here >
I love Sugar she is such a cute character btw!
Anyway the picture deserves to be in a Devianart Top 100 Sonic Deviations!
First critique done! Now to find another one