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?

I decided to write a critique because I reaaaally love your stuff and I want to try for once to say something more on a pic of your's.

This is so well drawn You are so good at drawing Sonic characters. The way you draw every part of the character is just.. excellent~ the eyes, the muzzle, the sizes of the hands, body etc... official work You make me jealous really.. I can't find something wrong on this pic xD
I really like the way you chose this kind of pose because although it's not simple (like just standing ones) you can see every detail of the character. And with this "showing off"(xD) pose it just makes the whole picture clear and cool

I don't think I can find any mistakes here.. even the shading is great. You can understand where the light is coming from. Btw I love those shoes xD Very cool character... Awesome job please keep it up!