rather than try to fully explain, I just did an edit.

I changed the chest to read more like I think you intended, IE a ridge along the middle. now it comes across as looking as if it's facing forward a bit.
The main changes were the head. higher contrast and a small rounding of the.... eyebrow ridge? and increasing contrast of the brightest skin value. I changed the eyes, mostly because they read as looking up a bit, but also to give them a better presense.
I uhh, wasn't sure if this guy was an alien or not, but i sorta removed the nose too? that one was just playing around really, feel free to ignore that.