THE BENTHIC SANCTUM
A lone DOOR stands alone, untethered by the concept of "walls". Intrigued, you turn the handle and step inside.
...
A poor decision, you quickly find, as you're immediately thrust into a DARK ROOM, flooded with WATER from floor to ceiling. The walls are covered with SHELVES, filled to the brim with a variety of (floating) GOODS. You think you see the SHOPKEEPER out of the corner of your eye, but when you turn to look, they're gone. Better browse quickly, before your OXYGEN runs out!