* FollowTheLeader: ''VideoGame/HalfLife1'' was inspired by the book.
* WhatCouldHaveBeen:
** The original draft included some more details about the setting that was left out. Most noticeable was that there was supposed to be a scene that shows the Arrowhead Project going wrong.
** Mrs. Carmody was originally to be depicted as eccentric to begin with. There's also a scene cut out that was suppose to show that her cult caused more casualties.
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