To summarize, Lightning Returns: Final Fantasy XIII takes place as the world is about to end. Lightning has thirteen days to save it and in Majora’s Mask style twist players will have to replay the game to save the world.
Lightning Returns: Final Fantasy XIII is the last piece of the Final Fantasy XIII puzzle and the game will have a happy ending. Forget about paradoxes because that’s the only ending, an interview from Famitsu explains.
Lightning is the only playable character in Lightning Returns: Final Fantasy XIII, but Hope will be present in the game. He gives Lightning advice through a wireless communication device. How is Hope alive hundreds of years in the future? A chaotic influence stopped people from aging, so you’ll see characters from Final Fantasy XIII-2 in the game too.
Square Enix changed the gameplay for Lightning Returns: Final Fantasy XIII. You can move Lightning around during battles and instead of selecting commands through a menu you press buttons to make her attack. Lightning Returns: Final Fantasy XIII still uses the ATB gauge system, but some moves require precise timing to pull off.
Lightning Returns: Final Fantasy XIII is described as a "world driven" game while Final Fantasy XIII was "story driven" and XIII-2 was "player driven." Novus, the world in Lightning Returns, is split into four areas, two continents have a natural feel while the other two are cities. In city areas players will see clocks that tell you how much time is left to save the world.
The game’s events are spread out through thirteen in-game days. Each one is roughly one or two hours. Events change how much time is left too. Completing a quest or defeating a formidable enemy may increase the world’s lifespan. Saving a person may reduce the time Lightning has to save the world. One major event in the game will have Lightning investigate a series of murders.
Because the game’s time changes it’s possible for Lightning Returns: Final Fantasy XIII to end before the thirteen days are up. If you challenge the game after a "bad ending" (but not the true ending) your items and other progress might carry over. Square Enix says they didn’t want to make Lightning Returns a game that will take dozens of hours to clear, it’s designed to be played multiple times.
Lightning Returns: Final Fantasy XIII is 30% done, Famitsu reports, and is slated for a PS3/Xbox 360 release in 2013.