i found this at
http://unlimitedgamer.net/kh2.php?id=coverage/kh2/rating_system_kh2.htm
Rating System/Obtainment of Abilities
Sora will receive a certain special ability/technique upon the completion of any one world (that is, aside from being granted the traditional theme-based Keychain, which will also be a returning factor). Exactly which ability/technique you acquire depends solely on how well you were able to successfully complete that particular world. Once you do complete the World, the factors will be tallied up, and depending on the end result, you'll receive one ability for that World. Determining factors include, but are not necessarily limited to (i.e. the only ones divulged as of this writing; these aren't the exact classifications [as there were none], just the names I'm going to give them based on descriptions):
Total Percentage Of World Beaten Rating
Overall Time Required To Successfully Beat World Rating
Total Vanquished Enemy-Count Rating
Battle Performance Rating
Magic Adept-ability Rating
Party Cooperation Rating
Group Participation Rating
Special Rating
Overall Performance Rating
Then, those are all added together and depending on the rating, you'll receive your reward. For example, in the Hercules-themed World (one publication referred to it as "Ancient Greece", the best ability Sora can obtain is "Zeus' Thunder", "an extremely powerful and punishing lighting-based magical attack", which drains all of Sora's MP. The second best ability is "Herc's Might" (drains 1/2) and the 'worst' one is "Hermes' Trail" (drains 1/4); no idea on what the latter two do (if you happen to do any worse than that, you'll receive a package with various items, equipment and lots of Munny included. There was no indication on whether or not if any of these abilities can be shared within the entire party, or if it's limited to just Sora. As well, if doesn't say if you can actually eventually obtain all the abilities for any given World by returning or not (I'd bet that you can).
im not sure if it is confirmed..........
