This is like some seriously impressive stuff :o
not only is the shading so well done, the style of the environment is on point, but what impresses me most is that if you were to remove the term "sonic" from the art tags, you would still very easily be able to tell it was him because you got his silhouette and eyes down absolutely perfectly despite only using two colours for him, and only part of his body being visible. (Even his quills are hidden, and you can still tell it is him)
Thats genuinely an amazing thing to pull off :o wow