Sisters, where the player would actively prey on the Little Sister, which would have alerted a Big Daddy and set up the fight with the player. This approach did not sit well with Levine, and 2K Games asserted that they would not ship a game "where the player gets punished for doing the right thing". They altered this approach where the Little Sisters would be invulnerable until the player had dealt with their Big Daddy, though LeBreton considered this "a massive kludge" into the game's fiction. The idea of creating the Little Sisters and presenting the player with this choice became a critical part of the game's appeal to the broader gaming market, although it was met with criticism from some outlets. Levine desired only to have one ending to the game, something that would have left the fate of the characters "much more ambiguous", but publisher pressure directed them to craft multiple endings depending on the choice of harvesting Little Sisters. Levine also noted that "it was never my intention to do two endings for the game. It sort of came very late and it was something that was requested by somebody up the food chain from me." Other elements came into the story design. Levine had an interest in "stem cell research and the moral issues that go around [it]". Regarding artistic influences, Levine cited the books Nineteen Eighty-Four and Logan's Run, representing societies that have "really interesting ideas screwed up by the fact that we're people". The idea of the mind control used on Jack was offered by LeBreton, inspired by films like The Manchurian Candidate, as a means to provide a better reason to limit the player's actions as opposed to the traditional use of locked doors to prevent them exploring areas they should not. The team had agreed that Jack's actions would be controlled by a key phrase but struggled with coming up with one that would not reveal Atlas' true nature. Levine happened upon "Would you kindly" after working on marketing materials for the game that asked the reader hypothetical questions such as "Would you kill people, even innocent people, to survive?", later working that phrase into the first script for the game. Numerous tensions within the team and from publisher 2K Games continued during the development process. According to LeBreton, Levine was distrustful of some of the more egotistical newer hires and was