Thank you guys!
Here's some early stages of the monochrome job, featuring several bg options: 1 = first layout; 2 = stylized volumes with highlighted edges; 3 = rounder volumes with shading; 4 = final monochrome.
All elements are layered, the small details are separate so it wouldn't be too much of a hassle to make heavy changes in the bg landscape.
It's true that I didn't give it as much attention as the fg, mostly for lack of time, and also I wanted the fg to be the main focus, so that it looked familiar to viewers who know the paintings. I used both variations of the amount of detail, and shading (getting darker the further back into the island) to convey this.
I don't really want it to be obvious iso, but I do want it to be good iso! I'll double check to find any sore problems, please point them if you see any!
I love st0ven's idea of making the skull into a hill more than a map, I'll try that right away =)
About the water, I'm not sure I get what you mean. If it's about the boat wake, it's a bit lame and I plan to improve it, mostly to fade it more at left and bottom. I had no plan to make the water more present, except maybe showing a vague transparency with the dark tones where rocks drop into it. It might conflict with the reflections; I might have to get rid of one for the benefit of the other, gotta try.
I won't go beyond that because the bg has to remain mostly uniform black (for printability, also I like the idea of that body of water being deathly still and dark), and also I don't think I've got the skillz for an acceptable large expanse of water!
