Very cool! Nice detail painting on the hydra and like the idea of the poor old redshirt's arm and the extra detail you did on the exposed bone and muscles.

Nice job.

Them red shirts can't get a break!

yes, very nice. the additional touches really add to the scene, although the rocks (where spock's foot is) could be painted would look better. i agree it could use more contrast on his skin, but also for the snake too, maybe a darker yellow wash over his underside to add depths to his creases there. the severed arm is a good addition and adds to the story.