Quoting Blake B.
Excellent job! How did you build the helmet arms?
Alright, I'll try to explain this without a picture. It is one of these things (http://www.peeron.com/inv/parts/4599)
with a round 1x1 stud on top. Then you just fit the helmet over that. I hope that makes sense!
I like the torso a lot. I personally would make the legs longer, though. They don't match the torso proportionally.
Not to spam, but I've made a couple Samus suits myself. Thought maybe you'd be interested in taking a look.