In your WIP, the second to last one has better shading than your final product.  The dithering is all over the place and not really necessary.  The other one looks like metal while this one looks... well i'm not sure what it looks like.  I thought it was a rolled up newspaper with  a face.  Also, the red eye, yellow eyebrow, and blue spots look completely out of place and just pasted on.  I would deviate from Metaru's palette and reorganize those aspects for a cleaner character design. 

awwww...  how... ehm... cute...

 But as far as I know, you should avoid dithering when working with metail reflections, you know, for the polished surface thing, etc.

(does it remind you those dancing cans that activate whit an applause?)