i like the concept. but why did you limit yourself to only 6 colors? the over dithering, especiallly in the sky, causes your peice to suffer. also you might want to try and use referance for your hands, even studing your own hands in the possition really helps.
on a possitive note your characters expressions are well communicated.
Thanks for the comments,
It was my first time practicing dithering and I agree it's overdone. I've also not previously limited myself with colour so I was keen to see where it went. Originally I was only using 3 colours but I couldn't get things how I wanted them. I'm not happy with how the rock turned out either. I think paper looks good though...