Im gonna throw this in for kicks and giggles, looks off balance to me. 

You've come to the right place 



Nice tree, can't bash the structure of it too much because there's nothing wrong with  .. Just maybe an increase in contrast, and some hue shifts. Keep your lightsource in mind.

Quickly had an atempt at making her a bit more shapely, pull it in at the hips and her figure flow more feminine.

Not too fond of the colourcount atm, like 22 or something I think, the character could be brought down to 8ish if you thought about it.

The arms a bit too long also, I'd bring it up to ere.

A little edit personally think he's leaning back too much, may be a characteristic posture but in my opinion it looks a bit too uncomfortable.

Not really changed the palette cus it works pretty well, I just think the shaded white area is maybe too dark. I'd personally use the darker yellow there, but I did give that colour a warmer tone.

All in all just tried to smoothen everything, not to fond of a full black outline so added some variation to that too.

Hope that helps, it's a cute character btw.

I think you've chisseled those muscles in there pretty definately haven't ya, looks very un-natural to me imho. It's pretty hard to work at this scale because fitting in all the details you want is almost impossible, just try work on the readability, hint want you're going for and im sure it'll come across much better than trying to hammer every nook and cranny in there.

I've made a little edit if im allowed, not sure whether you'd agree with slight style changes for the character but I just wanted to focus on representing the body to be a tad bit more readable.

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Also altered the palette a tad, trying to make it seem a bit more natural.

Changed the feet too, wasn't sure what this guy is gonna be used for, a platformer? But something is quite ambigious about the whole posture anyway, just needs to loosen up imo.

Oh and I don't think there's need to outline the beard, if anything a shadow to make it more visable but outlining things like that can just seem stuck-on and not apart of the face.