A few time ago I was imagining how Sheldon would look in a 2D fighting style (using elements like Head Explode, his Hulk hands, etc.) And these sprites looks really nice! :lugoi:
Spoiler: Just a little tip (click to see content)
Personally, I think Olof Linderoth (from Power Instinct Matrimelee) could be a good template if you want to continue his sprites someday:
(http://network.mugenguild.com/guild/anims/pim_olof_anim.gif)