Considering the incredible details on the body, such as the veins, it seems a shame that you haven't made his face more gnarled and such.
Having said that, it looks like you've made your own twist on the artwork whic is always good tyo see,
A near flawless execution from the original artwork. Bohun's comment leads me to believe that he has never seen a bat up close, I agree with him about the feet though. With that lunging pose they should be gripping the earth for added traction.
Apart from the head which is much too big, and not so good imo as the rest, a really interesting sculpt. Mayby the feet could also be betther: they'r flat, not dynamic like the rest of the piece, and not holding to the ground.