"PUNCH", the fictional energy drink Nicolas Cage's character drinks in the movie, has the text: "A fistful of caffeine for your kisser" on the can.
The screenplay was high on the Blood List, a list of highly anticipated genre scripts.
Liv's line "He's not trapped in there with them. They're trapped in here with him" is a reference to the character of Rorschach in the limited comic series/graphic novel Watchmen, also adapted in Watchmen (2009).