The small one if used for a game could be improved, at that size I'd definitly add a bit more contrast to the colours, because some details become harder to read, I'd also try and play with selective outlining, in a way that would bring out some of the details in the character, right now things get lot in the background of this site, andI'd almost garantee that would also happen in game.
Btw, going through your profile and loving your character designs,
>Damian: Thanks man... I have to admit I chose some very dark color( but the BG would be even darker... so replan is needed)... I will revisit them sometimes when I can( probably when I'm goin thru the sprite animation)