It has taken me years!
Really, this picture was about the only unfinished pixel laying around on my hard drive. It was only laid out a long time ago, with some details put in but not polished, so the most of the work has been done during the last week. Maybe four sitings of 3-4 hours each. That can be wildly inaccurate, cause I lose all sense of time when I draw.
Ok, so I've fixed the change in brightness and ergo atmosphere, and now I'm pretty satisfied with the result. That does not mean that someone else shouldn't play with it if he feels like it. The new version is not as smooth as the first one, cause hue shifts make individual indexes stand out more, but I think it is a much more exciting use of 16 colors.