PLEASE, don't link to images that have ".php=" in them, or preview your posts and make sure when the images are clicked, they won't make a new window pop-up (it's annoying :/).
You need to simplify the shape, at this size, all the variations you put in the sprite look like noise and it's impossible to see properly. Use bigger "blobs" of color, larger areas with the same color.
It's also a good idea to outline the different areas with a different color, similar to the most significant color of the area it's outlining. Blue all over makes it jumbled.
Make sure it reads well at least at 2x zoom. This one, it's hard to look at even at 4x.
