Looks good for a slug 
Poly construction seems fine.. you shouldn't run into to many problem with edge flow until you start modeling more complex organic specimens... such as human and creatures.
www.stevenegan-cgi.com
"Your weapons are no match for ours! People of Mars, surrender!"
"Um, this isn't Mars. This is Earth."
"Earth? Earth-with-nuclear-weapons Earth?"
"Yes."
[long pause] "Friend!!"