感謝非常。 ：D

好可爱的河童~~：）

I think I will do a little work to him at the bottom, but leave his shell the same. :D

 Why he sad?

I think the tummy is adorable the way it is.  The shell portion depends on you.  Do you want it to be like the actual shell of a turtle? - then the shell reaches to the edges of his arms and legs.  But, you've done such a nice job on the sides that it might be a shame to cover it up.  He does look a bit flat though beneath the shell portion.  Maybe all it needs is some shading there to round him out. (sorry for the long answer)