Let's see here. Gun looks terrible, you've resized it in a program you shouldn't have (Download GIMP to make your lines less jagged. Her entire body looks like a cardboard cutout that's slightly shin. The background makes no sense, the lighting would be completely different if you had kept that in mind, not to mention it doesn't really fit anyway. Bad fonts, bare shading and highlights and clearly your fingers need work. Boobs look okay though, haha.
Make sure your shading stands out more, otherwise it will always look like cardboard. Hair could be better but it's not inheritly bad. The gun is just terrible, the pose is silly anyway. The lines on her suit don't conform at all past her bust, and you need to practice your hands, we all do. Call me crazy, but I don't think Samus is the kind of girl to stand there and blush and look kawaii.. have fun with poses! You don't need to have your subject just stand in one spot.
Your proportions look good enough, mine are pretty shocking so I can't offer much advice about that. With the right tweaking and devolpment, I think you could do pretty well in this line of work (hurr line)
