A big improvent over your older work, It isn't pillow shaded
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I know this was an experiment to see if you could create something without pillow shading, but there are a number of other things wrong with this.. Sorry for the *reallly* quick, sloppy/lazy edit:
*You have over-dithered this, quite a bit, remember dithering can also creates a rough, brittle texture. I don't think that was the type of texture you were going for.
*This is very saturated, try and lower the saturation on some of the colours. Right now most of your colours are at maximum saturation.
*Why have you cropped the image like this? Right now it looks as though you have chopped of part of his head.
*Try to work on a more neutral coloured background, it makes it much easier to select appropriate colours when your background isn't upstaging your foreground. Also, it's much easier to look at.
*Why have you chosen to outline only the front of the alien?
*This species seems to have some very weird anatomy, where are its joints? muscles? bones? Think about these things when creating any kind of creature. Even if it isn't human.
*Try and use hue shifting, right now you seem to be using pretty much the same hue for all shades.