The Lunar Mercury is an amazing material idea!
I picture the star slime as having ferromagnetic qualities, or at least looking like those goopy, flow-unnaturally-up-surfaces fluids.
What a beautiful little jewelbox of stellar activities! I'd love to see this expanded with more art and more detailed hook-stories to bring folks to the site.
This whole module would work very well with my own Lunar theming in Outel's Edge.