Heya , my new pic =)
if u need that pic with more size, i can send u 1920x1080 pic =P
i wanna add something , but dont know what(

Great work would be awsome if you make the whole body

i think about this =) and maybe do that at free time=)

Your work too much depend on applying texture layers to image and pre-set brushes. I recommend you focus more on the drawing itself, then start adding effects to it. Also, I think that I gave u suggestion about shadows. Try at least some blur at the edges of the them, they are too ''precise''.

If you want to add something maybe foot mark would be good thing. Like boot foot mark, maybe of the astronaut who killed that alien. :>