It seems that unfortunately he reached his level cap.

Апельсиновый_Чувак said:
It seems that unfortunately he reached his level cap.

Says you; look at the change in coloring even from 2009 to 2010. A huge surge in detail in the coloring happens in 2008 and he's still improving, just look at the wide range of brightness and contrast.

Brightness, contrast, but i still adore the monochrome version the most, the others gives out the feeling of being made by a graphic program too much.

I think he has also been improving in term of the contours that he does.
His faces seem to have been slightly squashed but as he progresses he improves the contours, even if he goes back and forth a little.