Well, think of it this way, these things are the size of a hand and foot ingame, that would be small for a very high-poly model. That and I used hard shading, which emphasises the ....uhm....corners.
My qualms have mostly to do with the position hes in... I just see them as having their legs drawn in closer but with more hunch as well... not so much of a gliding-bat position.
That looks great!
The only things I'd change is make the inside flaps of the wings more pink (just the flaps not the "fingers" part of the wing), and the sprite has red-rimed eyes and mouth.
The position is flawed because I'm unable to view psk's with their according animation, so I used the static, older MD3 version.
The red around the eyes and mouth is there, although probably not visible enough.
The pinkness of the inside of the flaps is trickier because it's only on the inside while his backside is still brownish. And they uvmap of the wings was a bitch to figure out to begin with.