In this first-person shooter, players assume the role of Subject Delta, a genetically enhanced human (a "Big Daddy") who roams the underwater city of Rapture to protect a breed of "Little Sisters." Players' objective is to escape the city and thwart the plans of a villain who controls Rapture's citizens, who is creating large numbers of Little Sisters. As players explore Rapture's dark and dangerous wasteland, they will encounter its hostile mutated citizens, who attack and attempt to kill Delta on sight. Players use rivet guns, giant drills, and firearms (spear rockets, Gatling guns, shotguns, etc.) to defend themselves against the horde of frenzied humanoids. Special powers such as telekinesis, electricity, and fire/freezing can also be used to kill the attacking populace.
Intense acts of violence are as follows: players can use telekinesis to bring enemies close-up before drilling them to death—blood splatters in all directions; players can freeze enemies and allow them to shatter into pieces; players can set fire to enemies, or electrocute them in standing pools of water. In addition to the spurts of blood from combat, players will sometimes encounter smears of blood on walls and floors, and corpses lying in pools of blood—or spiked onto walls with rivets. When players come across a "special" corpse, they may set down the Little Sister and allow her to harvest ADAM (a DNA-modifying substance); the depiction of a child-like creature using a needle to draw fluid from a corpse can be somewhat unsettling (though overtly fantastical).
Consumers may wish to know that the game contains minor sexual content. While exploring Rapture's Red Light District, players can overhear conversations alluding to prostitution (e.g., "Hello there, how much? . . . Twenty bills and I'm all yours, sailor."); players may also see a variety of ads and signs for strip clubs (e.g., "Eve's Garden XXX")—these brief scenarios contribute to the Sexual Themes descriptor (i.e., the violence and profanity account for the Mature rating). The game includes frequent use of strong profanity (e.g., "f**k," "motherf**ker," and "c*nt") and some lesser four-letter words (e.g., "sh*t" and "tw*t"); in one instance, an enemy attacks Delta while screaming, "F**king sodomites everywhere!" [italics added]