new

http://i.imgur.com/UbnzE.png

I don't think masterchief fits in a underwater background. You could've worked more on this and it would look better.

Try to add softbrushing to the foreground so the lighting looks more realistic. Also, the background does not suit what you have so far, at all. I wouldn't suggest changing it because that would take too much time, but giving it a strong blur would definitely eliminate the underwater element you have going.