The moon is full every time it's shown in each episode, no matter how much story time has passed.
The author of the show's sourcebook, Todd Grimson, was partly inspired by the vivid dreams he began to experience after he reportedly became housebound due to an incurable, degenerative disease (multiple sclerosis).
Instead of appearing as an overnight success as she does in the Netflix series, in the book, Lisa Nova has a longer résumé: She's already co-directed a feature, Girl, 10, Murders Boys, about the Mary Bell killings and early in the novel attends a film festival in Seattle where they're screening her feature and one of her shorts, an ultraviolent film called A New Asshole. You see her put up a poster from Girl, 10, Murders Boys in her apartment in the series, but it isn't otherwise mentioned.
Boro's talon toe nails were Catherine Keener's idea.
The trapdoor represents l'appel du vide, or "the call of the void".