It's'a pillowshaded!
Line art is nice, coloring is not. It's more or less just flood fill with some low-contrast nuances hugging the outlines - not pleasing.
I think that if you just made all the color spaces flat, completely without shading, your image would look much clearer, crisper and pleasing.
And then I think you should reshade it from there with more contrast. Try to shade with big color blocks with the same confidence that you draw solid shapes in your lineart - it's the same theory - you don't TINT the 'filling' of the lineart, you draw new clear shapes within it to show form.
Get it? I don't think I'm being clear
(also I really like this spriteycharacter, so don't feel hurt, I just want it to look even better <3 )