I have never seen the original piece, but this looks very spectacular--I love how smooth it is... but it's rather distracting how the piece is finished...perfect...in some areas, but then right next to that spot, there's still messy lines and unfinished aa, etc. (this is a wip though, right? so it's understandable.)
I feel this could benefit from dithering, like on the skull, and on the bone below it, and the blonde guy's left arm. But all in all, this thing is really cool...if I wasn't so lazy right now, I'd look up the original...