Kingdom Hearts: Birth by Sleep

Kingdom Hearts: Birth by Sleep is another spin-off on the PSP, from the same team that remade Chain of Memories (Re: Chain of Memories) for the PlayStation 2. It was good enough to get a Final Mix version in Japan.

Unused Areas
TxX9huOsGF0 Unused areas from a scrapped world for The Jungle Book are present, along with two scrapped rooms from The Sword in the Stone, and an area for a "Mysterious Wasteland".

While a number of areas can be accessed in the Final Mix version, the whole thing is in a very unfinished state: most textures are missing (excluding Louie's Throne Room, which is fairly finished, and the other non-Jungle Book related rooms), and entrances and pits are not properly programmed.

Unused Items
[ULJM-05600] _C0 All Keyblades (Ven only) _L 0x8172A7CE 0x000E0001 _L 0x10000001 0x00000001
 * Light Seeker (ライトシーカー): A equipable Keyblade for Ventus, which is another version of the Kingdom Key D. Can be re-enabled with the following CWCheat code:

Characters
Pleakley from Lilo and Stitch has an unused model in the initial release, albeit lacking textures.

Kingdom Hearts 3DS: Dream Drop Distance Demo Leftovers
In the Japan-only Final Mix re-release, there are some unused 3D models, that came right from... the 3DS game demo version. Interestingly enough, cutscenes can be hacked to include these models, and their animations, fully working. This is a not-so-subtle hint that Dream Drop Distance uses a modified Birth By Sleep graphical engine. The unused models include: There is also the logo of the demo version of the 3DS game, called simply Kingdom Hearts 3D Demo LCmNvYlNfBE 1X-JVncMMuY
 * Sora
 * Riku
 * Kairi
 * Xemnas
 * Ansem, Seeker of Darkness
 * Twilight Thorn