so many people dont understand these three games and since they mean a lot to me ill help clarify.
ff13-jrpg, but trying to push the atb system to the max. the battle system is menu based, but the attacks seem to come out in mostly real time. there will be pretty big battles as some trailers have you fighting more than ten enemies at a time, a rarity in most jrpg's. the summoning will be unique and have more uses than just attacking. shive seemed to be a motorcycle, which might mean they are all forms of transportation. the engine is the white engine that se is developing to make cg quality fights. it is being developed specifically for ps3. the story is about an elite class that has blocked the outside world from coming in. the world is the most futuristic world seen in an ff game. as lightning, you are fated to destroy it. being part of fabula crystal novalis, crystals play a main part in the story. in this the crystal have some sort of sentient though and they are what is keeping the elite class sheltered.
ff13-action rpg, with no direct relationship with ff13, other than being in fabula crystal novalis. the battle system revolves around weilding 13 weapons. you can somehow control all 13 at one time, but whether its passive or personally controlled is unknown. the unwielding weapons can be controlled using some sort of telikintices, but it is unknown if they are specific to the weapons or it is a general power. the battle system involves teleportation, seeming to allowing you to teleport where ever you throw a weapon. The story is about a prince with the last known crystal in the world. it has a magical modern setting as can be seen in the architecture and the car in the trailer. almost nothing is known about the story and no actual gameplay footage has been seen. it also uses the white engine.
kh-an action rpg, with relationship to ff's except through cameo's. the battle system uses a limited menu system, which gives versitility to using many different actions in an action game. the menu is slow, but it also gives you shortcuts to commonly used actions (only magic in the first but both magic and items in the second) and it defaults to attack giving a more offensive feel and not having to selcet most attacks. the battle system is based around ground and air combo's along with numerous abilities that augment the attack along with items and magic to support the offensive nature of the game. the story is about three teeanagers who are separated when find their world destroyed by a dark army called the heartless. it is a universe based on the heart and the delings with good and evil, light and dark, power and love. the disney worlds are their own mini stories, tweaked ever so slightly to both allow the the heartless and incorporate them into the main story. there is both a continuing story based off of the characters from the games so far with a questionable important cell phone game, a spin off for the ds to delve deeper into the workings of an enemy force, and a prequel for the psp which is supposed to answer questions about the keyblade itself. A third main game will be developed, but neither system nor even if production has started is known. the universe is still small and easy to get into. the second game (not including com, which can mostly be skipped but does give some insight) has an intro but you wont get the most out of it unless you have played the first game.