I agree with shadow wolf, and halfly with shark,. i think this is somehow pixeled, but not with too many skill
most likely this is a photo trace. nothing against them, but next time please inform unknowing people about that.
I think that you cold do a lot better on the shading, and detailing (the folds look good, but those are pretty easy when you have placement ref./trace) you use a very, VERy big amount of colours, of which most are just used for a 1 or 2 pixel line.
Then, the details are.. well.. missing actually. if you look at the piece 1x, it looks like a photo that had been hit with the blurry stick. look at his eyes, mouth, the overall head actually, and you'll see that it is all very bland and plain and .. welll.. blurry
AA-ing is not about ''how to make something look not edgy by blurring it'' but more ''how to put lpixels on a line/area as to make it look smooth though not blurred''
.. i should make tutorials about it sometime =P
and lastly, your colourschemes appear pretty linear, try adding some more hue shifts
Well, maybe it actually WAS a photo and he edited it so it looks drawn....
It's a bit too good to be true......