Yes. The premium member critique system is just to make it easier to get critiques. In fact when I joined DA, they didn't have it. It was an added feature. If you want a critique, just say so in your comments about the piece you want looked at. You can either ask in ThumbShare Forum or join a groups who has critiquing as a focus or a group who have a folder for artist to put pieces in to be critiqued.
if you will can you check my art and comment on them about how i can improve, thanks