Very nice, I recognised this guy staight away( but from where I don’t recall…)
I wouldn’t be concerned with making him exactly like the original.
Two things jump out at me:
there is quite pronounced shadow detail on the body, but
none for the ground. Giving him a ground plane to stand on
and receive shadow detail may make this render more engaging.
one arm looks much longer than the other. I think this
is just the pose - but it is worth rethinking either the
camera angle or the position of the arms to make them
look more balanced.