Lots of conspiracies/cover-ups/etc. Brings up the real-life issue of overpopulation but doesn't address the specifics of what will happen or offer potential solutions (other than the deadly one the heroes try to stop). But the issue could be worth discussing with older teens. Langdon encourages a character to invent things.
Violent, disturbing imagery. Nightmarish visions of hell on Earth with twisted, disfigured, diseased people; burning; rivers of blood; etc. Bloody wounds. An IV is yanked out of a hospital patient's hand. Guns and shooting. Fighting. Stabbing with knives. Hypodermic needle jabbing. Fire extinguisher in face, spraying chemicals in face. Falls from great heights, bodies hitting the ground, hard. Characters die. Explosions.
Fairly short scene of kissing and intimacy.
A use of "f--k." Also "s--t" and "damn." Use of slang term "gone t-ts up." Use of "in God's name." Many uses of "hell," but not as a swear word.