Iron Man

I think it needs to darker aye.

Edit:

 

Your render need to blended into the background. It looks like u just make the backgroudn then stuck the render on. Smudge it more in and don't darken it, it will be to dakr.

 

don't see a flow going with it, it looks like u tried to make it with some winframes but the bg goes against it

 

its plain, render fills up most of the canvis