* HeyItsThatVoice:
** The Little Sisters are voiced by Jodelle Ferland, who has experience playing a CreepyChild in films like Film/SilentHill.
* WhatCouldHaveBeen: A DummiedOut idea for the plot would have involved [[DirtyCommunists Soviet soldiers]] invading Rapture. Part of the AI coding intended for the Russians eventually ended up being used by the splicers instead.
** A removed message from Eleanor revealed that Delta is her biological father (Sophia picked his DNA randomly from a bunch of archived DNA).