Well, in that case a lot depends on how are you gonna animate it, but i notice some issues in shape too. I guess your game will be in top-down view, like almost every rpg game on byond, and we've got here side view, so if it wont be platform game, you made it a bit wrong. Take a look at my doryuudon, its not perfect, but i just want to show you what i mean
You could raise saturation a bit, its too gray imho. And correct the lines, they're dirty. You also used that dark red only in 2-3 pixels, you dont need that color at all. Dont affraid to use contrast, because with higher contrast defining shape is easier. And try to make it more 'mud-like', take a look at your reference.
Well, in that case a lot depends on how are you gonna animate it, but i notice some issues in shape too. I guess your game will be in top-down view, like almost every rpg game on byond, and we've got here side view, so if it wont be platform game, you made it a bit wrong. Take a look at my doryuudon, its not perfect, but i just want to show you what i mean
http://img822.imageshack.us/img822/6364/dotono.png