An Introduction to Dissidia

Dissidia: Final Fantasy, a Final Fantasy character brawler slash action RPG, was released in Japan on 18 December 2008 and 25 August 2009 for North America (September for Europe). It features ten heroes and ten villains from the FF series pitted in an eternal battle for the forces of good and evil, respectively. It also has crystals, and yes, they do have to get them all.
Although the story is straightforward, the gameplay makes up for it. It is at once simple and endlessly complex: the object is to drive your opponent's HP down to zero, but characters can be highly customized between the ability and accessory systems. It takes a while to get the hang of how it works, but once you do it's quite addictive.
The game is divided into different modes of play. Story mode is broken up into ten paths called Destiny Odysseys, one for each hero, after which there is the final path, Shade Impulse, to Chaos. (In the English version, Shade Impulse opens up after clearing any Destiny Odyssey.) After defeating him, three more paths become available, each harder than the last. Quick Battle allows you to level up the characters (including the villains once they're unlocked). Network mode lets you fight other local players wirelessly. After Shade Impulse is cleared, the Duel Colosseum is unlocked, which is an endless series of battles. In the English version, there is also Arcade Mode, which allows you to fight with pre-customized characters in a series of battles from the get-go.
Dissidia is a game for fans of the Final Fantasy series first and everything else second. In this it does its job incredibly well; it's nothing less than epic win to see the heroes of old fighting against the recent villains and to see Bartz and Zidane gang up on Squall. The help pages are even written in the voices of classic series characters. While casual FF fans may find Dissidia enjoyable, it's the die-hard fans that'll love it, myself included.
This section will be expanded when I've had time to play the English version of the game.