Final Fantasy X-2 is an RPG developed and published by Square Enix, exclusively for the Sony Playstation 2.
Final Fantasy X-2 is the only game from the series that is a direct sequel to one of its games (here obviously being FF X). The game starts takes place a couple of years after the defeat of Sin during the "Eternal Calm" era. Yevon has been discharger leaving the world of Spira without any religion (the religion was based on Sin so now that he?s gone, there's no real point to it). Yuna is still the main character of the story but has left all her summoning quests behind to become a sphere hunter, spheres being some sort of video tapes with recorded memories. The game starts when you find a sphere showing you Yuna's lost love, Tidus. Your quest for answers begins. During your quest you'll discover a lot of new characters as well as the ones from FFX. Locations also are the same but new areas can be explored (ruins in Mount Gagazet for example).
This is the first time Square Enix offers us so few playable characters: Yuna, of course, Rikku, who was also in FFX, and a brand new one, Paine (which replaces in some way Lulu and Auron at the same time). However, this is compensated by a new system called "Dress sphere". During the game, you'll find new clothes for your characters which alternate their abilities (each dress applying to a specific class: white magician, warrior, thief...). This enables a new strategic approach as you can change clothes during battles and some abilities can only be used with certain of them.
Another innovation of the game is the return to the active combats (well not really an innovation, since all FF games use this method except for FFX). The battles are no longer turn based and you'll have to wait for the action bar to fill up to act. This gives dynamism to the game and accelerated battles.
Final Fantasy X-2 is a great sequel to the original, offering an original story and not just relying on what the previous game had done. In fact, a part from the fact that it follows the same story, both games are entirely different. Nonetheless, it's difficult to follow and understand the story if you haven't played Final Fantasy X.