As we can read on Wikipedia, Kingdom Hearts: Birth by Sleep is an action RPG developed and published by Square Enix for the PSP. The game was released in Japan on January 2010 and it is planned to be released in North America and in Europe on September 2010. Development of the game began in June 2005 and was originally intended for the PlayStation 2 with Sora as the prototype protagonist of the game.
Birth by Sleep was developed by Square Enix’s fifth Product Development Division, based in Osaka, the same team behind Kingdom Hearts Re: Chain of Memories, and uses the same graphical engine as Crisis Core: Final Fantasy VII.
The plot was completed for the PS2, but development was halted six months after it began due to development of Re: Chain of Memories. The development team changed the platform to the PlayStation Portable so as to make use of the PSP’s functions such as co-operative and competitive multiplayer gameplay.
In August 2009, new Famitsu scans revealed a revamped User Interface (having been revamped twice before) as well as new worlds after a lack of news for close to a year.
As posted by Granville in our U64 Forum, hidden in the final game’s code there is a very cool secret world that was cut, but that you can still access via hacking! It’s a world based off the classic movie The Jungle Book.
The first area is in the Monkey Temple of the orangutan Louie. The other areas are your basic jungle type areas, although they are all clearly incomplete and lack a lot of their texture work. I’d say the Temple is the only complete area. The only way to access these areas is via hacks, they were never used in the main game and no images were shown in prerelease photos. It’s a pretty interesting find actually. A hack hasn’t been released yet, but i imagine it will soon.
On Youtube we can also see a video of Keytotruth, who managed to hack his/her way into the data and play around in it.
Thanks to Granville for the contribution!