I saw your piece on PJ too, the pixel job is pretty good, but I don't really understand the drawing though..
the alien is on the right, but I really don't know what is the orange under the eyes (tears?) and the purple thing under that (a mouth?)
if it's a mouth , the shape lacks a bit structure, and the lighting should be opposite.. (the light comes from above so the balck should be at the top and purple at the bottom..(if it's a hole)..
I don't really get the pink thing neither...
otherwise AA & dithering look good..
after few minutes
ok I understand what is the orange under the eyes, it's kind of antenna holding the eyes right?
then check you shadows, cause mainly your lighting comes from the middle of the picture, so the shadows should go to the right.. and right now they go to the left .. pretty confusing...