Despite all the vulgar humor and bad behavior, the movie's point is for characters to learn how to be good. As they discover, simply being "nice" isn't good enough: They must consider others before they consider themselves. At the same time, two old friends learn to talk with each other and renew their failing friendship.
"End of the world"-type violence, including some giant, rampaging monsters, cars crashing, etc. Many characters die. Characters are possessed by demons, crushed, stabbed, impaled, and/or shot. A man's head is ripped off and rolls around on the floor, spilling blood everywhere. Some humans become cannibals, though no flesh-eating is shown. When Emma Watson shows up later in the movie, the men have a talk about trying not to "rape" her, which comes out badly.
A porn magazine is briefly shown. A giant sculpture of a penis is shown, and some of the giant computer-generated monsters are shown with penises. Also heavy, constant sex talk and innuendo. A male character slaps a female character's behind in an early scene at a party.
Language is extremely strong and constant -- mainly "f--k," but also "s--t," "c--t," "c--k," "p---y," "prick," "t-tty," "ass," "a--hole," "bitch," "bastard," "damn," "hell," "goddamn," "oh my God," and more.
Characters fight over the last Milky Way candy bar in existence, and when they finally eat it, they make breathless "yummy" noises. (It's a great ad.) Several other brand names are mentioned. Since the characters are playing themselves, many of their actual movie titles are mentioned.
Drinking, Drugs & Smoking
The movie begins at a Hollywood party filled with drugs and alcohol. A character blows cocaine in someone else's face. Two main characters spend a day smoking pot at the beginning of the movie. After the apocalypse, the survivors take inventory, and most of what's left consists of pot and alcohol.