Looking like a nice start.
You have allot of edges running down the back for the length of the body. From head to tail. You don't want to have any edges clustered in small groups, if you do, when it comes time to smooth the model. Your going to have really dense patches of geo, and other that can barely hold they're form.
As a rule. Your geo should be evenly spaced, or at least as much as possible.
"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?"
[long pause] "Friend!!"