The ESRB have published their ratings report for Red Dead Redemption 2, detailing a list of factors that have gotten it the infamous M for Mature rating in the U.S.
Beware, this list may contain minor spoilers.
This is an action-adventure game in which players assume the role of Arthur Morgan, a member of an outlaw gang on the run in 1899. From a first- and third-person perspective, players traverse an open-world, Wild-West environment; complete mission objectives; interact with characters; and engage in gun fights with lawmen and other outlaws. Players use bows, pistols, shotguns, rifles, and explosives to kill enemies in frenetic combat; shooting enemies occasionally triggers a close-up, slow-motion view of enemies getting shot and killed. Players can also use tomahawks and knives to perform stealth kills to eliminate enemies discreetly. Large blood-splatter effects occur during battle, and some weapon attacks result in decapitation and/or dismemberment, leaving bloodstains and body parts on the ground. Campsites and cabin environments sometimes depict severed body parts and corpses with exposed viscera. Players may also engage in various criminal activities (e.g., robbing banks, shooting civilians), though this will negatively impact players' progress (e.g., wanted status, pursuit by lawmen and/or bounty hunters). Cutscenes also depict intense acts of violence: a man executed from the gallows; a character shooting himself in the head; a man repeatedly electrocuted; a bound man set on fire. The game contains instances of nudity and brief sexual content: a woman (breasts exposed) straddling a man inside a brothel; a spanking scene that is depicted from a distance and includes a fleeting depiction of male genitalia; sexual moaning sounds inside a tent; male characters with exposed genitalia in non-sexual settings (e.g., a man swimming in a river, corpses on the ground). During the course of the game, players' character can engage in a drinking mini-game in which alcohol is poured for drunken bar patrons; players' character is also depicted drinking alcohol, sometimes resulting in screen-distortion effects and impaired controls. One of the stimulant power-ups is known as Cocaine Gum, which players' character can chew; in one scene, characters can briefly be seen smoking from an opium pipe. The words “f**k,” “n**ger,” and “sh*t” can be heard in the dialogue.