Unlike most Final Fantasy games, Dissidia is more of a fighting game rather than a classic role playing game. It still keeps the complex story, character level-up and customization though.
The game features main characters from the other Final Fantasy titles, two from each title (the protagonist and the antagonist).
The plot revolves around the battle of the two gods, Cosmos and Chaos. The protagonists will form teams in order to fight through Chaos' armies and find their crystals which will later be used to destroy Chaos. Each character has his own campaign to go through at the end of which a crystal will be collected.
The game also features a single fight and an arcade mode where the player will be able to choose his fighter and the opponent (opponents are automatically chosen by the game if playing in arcade mode though).
All of the character's experience and skills received through the campaign are saved for the other game modes (and vice-versa, for example: if Cloud had a level equal to 12 when completing the campaign, he will also appear to have the same level when viewing him in the character roster in Arcade or Quick Battle mode).
Another feature is that the items you find during the campaign belong to you, the player. That means you can move items from a character to another.
The game also features extra content such as villains, costumes etc. which can be unlocked by using PP. You get such points from each fight and completed campaign.