The amount of detail you've created with +-6000 polies isn't bad at all
The unnatural sight of the arms could be caused like lostclimate already mentioned, through the way it's been shaded but I think there is another reason. The hands are to small compaired with the rest of the arms, it makes it look like a pointy unnatural arm. Maybe try to broaden the hands beginning from the wrist up on to therest of the hand The model qua from is oke, anatomically not perfectly correct but good enough, the textures are nice too but abit to shaded.
In overall, this looks quite promising ^^ !!

Cheers

Frazzle