There's a bit to much of a difference between the dark parts and the lighter parts. Close the gap. Also, make the render stand out more whichever way you want to. I usually just duplicate, gaussian blur, then overlay the layer.
I didn't use brushes ^_^. All defaults except the C4D. I use smudging alot and I feel that I got good at it so I try to spread some in every sig lol.
How did you make those pixelated squares? Also what program you use? These are pretty f%cking intense.