Well, they are pretty simple, but I guess that's the way you wanted them to be. You should get more action pictures. It would be badass to see a squad of the ODSTs against some brutes. Also, maybe better angles. The ones you have right now are a bit akward.
for sugestions i would also have to say camera angle and in the first one you didnt need the big thing on the right in the picture
all but the last are pretty decent. that 3rd one's light is surrounding a point of interest in the pic - the grip and trigger. Another thing. This should be moved to the Screenshots forum, in the Screenshots discussion forum.