Hi there!
Your character has a nice design, its interesting without being too over the top. I particularly like the design of his boots. Pendulum -the band is such a cool springboard to use for a character.

I don't know ennough about computer colouring to give you much advice here, your cell shading is cool and fits the Sonic-style well. Personally, I would have liked to have seen a bit more contrast on the Tan areas of his gloves and boots. The green, white and flesh-coloured areas all have plenty of contrast, but his gloves and boots look a little flat to me.

Anatomically- its pretty darn good (within the sonic universe ) I knew straight away that he's a male echidna, and what all his limbs are doing. I think that his tail is possibly a bit too big, but maybe thats part of his character design? Also the crease on his crotch freaks me out slightly.
I love his dreadlocks though, they're pretty sweet.

Overall I really like this drawing, its appealing and nice to look at, and thats the whole idea right?