So, after more then a year I finally finished the challenge: make a 16-color palette and draw 3 different pixer arts with it. The challenge included keeping color count to only 8 of these 16, but I could not keep it in this last piece.
Well, kind of finished...I can still see many rough spots (like AA) and I am not happy with the clouds or some of faces in the top frame, but that is as far as I am taking it, else I will stick with it forever... time to move on. All comments, opinions and critics are really welcomed, though.

 Here are the links for the other 2 parts of this challenge:

http://pixeljoint.com/pixelart/109389.htm
http://pixeljoint.com/pixelart/109214.htm

The original is part of the manga One Piece, by Eichiro Oda, from one of the best arcs in all its huge series.