This could be great, but needs some attention into details!
Jaggy line art and useless/poor dithering would be the main points. Not a big fan of the white stroke either.
Loving the expression =)
I like the style (he's cute 
), but I think you should work on the background, because it makes a bit empty like that 
Yes, the whit line is a bit distracting, maybey add light aa around pupils. Overall really cute, love it but needs work :)