Wow, great ideas. It looks like you are doing it in sections so you can carry it upstairs. Once it is in place use a few small pillars to join shelves and run a few branching pieces at angles so it doesn't look so linear/striated.
I like the barnacles. Try to add more. Clusters of mussel shells embedded in the back wall also makes it look more realistic and adds more texture.
Try not to make the wall flat with uniform shelves. Leave one or two panels simple to break up the pattern, or use a lot of cement to bring out the background layer.
Another tip is to use a large lag bolt and press the threads into the fresh cement. This will make worm fossils. Use different size bolts and keep washing them in water to clean the threads. Screwdrivers can also make nice worm holes and scratch some texture into the cement. You can mix some extra aragonite and small shells into the cement mix for some areas for extra texture. WHERE ARE YOUR RUBBER GLOVES! Oh yeah, you are a professional builder
Use different technics in each area. Mix some cement wet and let it slump, and in others use it dry for a different look. If you handle the cement too much while forming it you work the water to the surface and loose stability in sculpting. Because it isn't structural you can throw some dry cement powder right on the surface if it is too wet.
I had some success with blasting the wet cement with an air compressor, but forming by hand was best. You have to let it set for a bit and form it when it is just right. A slightly damp sponge is the best tool for feathering edges and joints. Keep rinsing it as you go.
The nice thing about working with dry rock is you can keep adding layers of cement until you are happy with it.
Keep up the good work!