I made a few minor edits to your last (pre-desaturation) version, nothing really important since you already did a very good job
I applied more detailed shading to the head and the tail, increased contrast in a few spots (particularly his shirt) and added some highlights.
More importantly though, how about making his tail yellow instead of blue? Blue tail blends with his pants, so the tail is sorta hard to make out when looking at the picture.

More importantly though, how about making his tail yellow instead of blue? Blue tail blends with his pants, so the tail is sorta hard to make out when looking at the picture.
