SD what exactly was your intention? All i see is a simple bg from google with a sphere in front of omega, and a try to make flow around omega. Am i right or did you do something more there?

He probably want to show us how cool omega is, lol

the sphere in front seems to be stressed as it is so eye catching, but i can't really understand what he did here before he tells me

Actually the BG is from a deviantart cosmos package , they're really good http://resurgere.deviantart.com/
i don't really have an intention it's just something i made since i haven't done anything in a while
i did alot of work on the sphere though , and alot of color balancing and brightness/saturation stuff
i thought of vylon omega because i just really like vylons

here's an improved version

Well as i suspected, you worked mainly on the sphere.
From the things you said above i come to this: you used a bg from deviantart that you think suits vylon omega, you smudged his wings etc a bit, and you worked much on the big sphere in front of him.

There is not a lot to learn about spheres and their design - they are simple ball-like bodies which you customize to make them fit the rest of your image.

I will now focus on your sphere itself ignoring the surroundings - i can see the swirl of dust in the center of your sphere, an arc can be seen on the right bottom, the other part of the sphere circle is smudged at the top so it kind of fades away, on the left bottom i can see the dust coming into the sphere from outside, the sphere is shining and fading away which is not appropriate, and maybe its size is too big

Now lets not focus only on the sphere, but the whole picture: vylon omega is a yellow-orange-dark grey render, the background is dark blue-purple colored, and your sphere is white-shining blue colored
Here you have a variant of the "purple-yellow-cyan" color scheme which is in your case "dark purple-yellow orange-shining blue". In my opinion, having yellow-orange and dark purple only would be much better, so you can try changing the sphere color to make the picture look better.
But where's the problem then? You don't have any flow in your picture. To accomplish flow, you must have a good environment that fits both omega and the sphere. Omega is hard to play with because of his wings. A sphere that represents the attack of vylon omega should have more dust tails approaching the spere from outside so it looks like he is charging energy for it, the position of your sphere should be more close to the arm behind it, the background should match the dust but on your picture it doesn't really match.

These are the critics for you to improve your skills and thinking while making the picture. To have it easier, you shall work with smaller image sizes, this is too big to begin with.

I understand that you worked only on the sphere but i wanted to make sure you know the stuff i said above. I'm pretty sure you learned a lot with this sphere try and you're going to use that knowledge on some other things too. Here is a site for color schemes i recommend: http://www.colorsontheweb.com/colorwizard.asp
So i can say well done after all bro, i hope this helped a bit