Nicely done! Two little things:

1) You might want to apply a blur or something to the outside gradient that you use to get the coastal lines to prevent them from getting too blocky. I'm not sure of the technique that you use but one of the things but I've used the blur trick to get rid of some blockiness in subsea areas of maps that I've used before.

2) The hachures aren't quite right in terms of direction. They should always be perpendicular to what the contour line would be at that point. Wikipedia has an article on the subject ( http://en.wikipedia.org/wiki/Hachure_map ) that might be of interest.