The Entertainment Software Rating Board has rated Final Fantasy for North American gamers, giving the title a "T" for "Teen". According to the ESRB description, that could be a "T" for something else.
Note: The ESRB blurb might contain what some could call spoilers. It does contain boobs. Side boobs.
Players assume the roles of heroes caught in a war between two opposing forces in this fantasy role playing game. Players travel between the planet Pulse and a moon named Cocoon to engage in missions for magical beings called the "fal'Cie. Missions involve battling enemy soldiers and creatures by using melee attacks (swords, knives, staffs, etc.), firearms, and magic spells (lightning strikes, fire blasts, etc.).
Combat is executed through a modified turn-based system in which players select various commands from a menu while freely moving one of three heroes through the battlefield. Players can also summon elemental creatures to battle an assortment of goblins, golems, zombies, wolves, frogs, bats, and robots.
The game's cinematic cutscenes contain the most intense depictions of violence: machine gunfire from space ships strafe human characters below; humans and robotic soldiers exchange gunfire-aboard vessels, on the ground; a slow-motion gunfight depicts the cracked lens of a robot shot in the head by two semi-automatics.
Cutscenes occasionally depict female characters dressed in revealing outfits: Holographic dancers-clad in bikini tops, skimpy leotards, and backless chaps-glide above the city during a festivity performance; flying-motorcycle models wear skin-tight tops that expose deep cleavage. And during one elaborate sequence, a female character transforms from a crystal statue back to her human form-sparkle effects, camera panning, and shimmering lights partially obscure the nude character, though side-portions of her breasts are visible (fleeting-one-to-two seconds). The game also contains the expletives "a*s," "damn," and "hell"; however, it is the violent content, the suggestive themes that account for the Teen rating.
Enjoy teenage gamers!
Final Fantasy XIII [ESRB via Siliconera]