Level finishing, Lighting and atmospherics, Refactoring and values tweaking for surface materials, making of underwater and ground shaders, background meshing, optimization.
Level was pretty much done by Rick Kohler when I got it to my hands, originally it was only about making ground and do something with water, but step by step it starts changing and updating, first background meshing, then lighting and mood, then had to tweak most of surfaces to make them work better with lighting, fade rocks by world height to avoid unneeded reflections on top of the cave and make fog more pronounced, adding foliage, underwater post process material, etc.
I didn't really made any asset besides shaders, most of the time it was about reusing existing assets or modifying them.
Base level meshing by Rick Kohler
Most of textures made by Josh Marlow