Actually I think behance is like the biggest site where you can find commercial art in graphic design / architectural previsualizations or advertising, plus it's backed by Adobe now. I would definitely not call it amateurish, but it might not be ideal to showcase real-time art (you're mostly limited by image size)
Some advice I'll share: Your portfolio is only as good as your weakest piece. Learn to maintain consistency. I almost made the mistake of being too attached to art that wasn't helping me at all. Focus all your energy on only showcasing pieces that are meant to look good. If you worked on something you didn't give it your…
Generally speaking, portfolio feedback is best posted in the "3D art showcase & critiques" forum. I would advise removing the character and 2D work and concentrating on environments and props. I say this because they are bringing the overall quality down. In your environments I'd like to see better materials, learning some…