Deeper. That's the term (aka the "north star") the developers at 2K Marin has used to guide them during BioShock 2's entire development process. In terms of narrative, deeper comes in the form of venturing further into Rapture's lore, failures, nightmares, misguided idealism and doomed beauty. Your role in the game is that of a Prototype Big Daddy, the first of his kind. At one time he was bonded to a Little Sister named Eleanor before some devastating event occurred, severing their connection and sending him into a deep sleep. The story opens with the Big Daddy waking up and deciding he must traverse Rapture in order to find his long lost Little Sister (aka "his rock").