Well, since no one else is gonna , I'll say something. I like the colors for one. It's a very attractive combination that gives kind of an earthy feel . Which is cool because it's not something often seen in space costumes.
I'm going to assume you purposely exaggerated the proportions of the lower body, something I do on a regular basis, and as long as it's consistant I don't mind. I think for me the things that kinda poke at me the most are her arm (the one saluting) and her chest area.
The shading on the arm flattens it out emmensly, and makes it seem like it's devoid of any type of contours , be they muscles, joints etc.(the same could be said for the knee area to be honest) The chest bothers me because it seems like an odd meld of pectoral muscles and breasts. That is, they could pass for pectorals if they wer a little less rounder, but they could also pass for breasts if they weren't so high and squarish. It's hard to explain.
I'm iffy on the facial features' proportions as well, but I'm not sure what you were going for , so I'll leave that up to personal preference. Finally, your pixel art is pretty delicious, but that photo-chopped background is totally clashing with it man.
Anyways I hope that helps!