Kingdom Hearts: Birth by Sleep, perhaps one of the most anticipated PSP games in 2010, is only available on a UMD and in stores. That means PSPgo owners won’t get to play the Kingdom Hearts prequel or visit Stitch in Deep Space.
Why? Tetsuya Nomura said to Dengeki in a Dissidia 012[duodecim]: Final Fantasy interview that he does not want any misunderstandings. The problem does not lie with Square Enix, Disney or Hikaru Utada who performed the game’s theme song. "It’s difficult because of a reason I cannot say," Nomura explained. Nomura says he is thinking about how to make a downloadable version available, but he needs more time.
Square Enix published Kingdom Hearts: Birth by Sleep in Japan over a year ago. Recently, the publisher has begun to make their PSP back catalog available on PlayStation Network. Final Fantasy, Final Fantasy II, and Final Fantasy Tactics: The War of the Lions are all coming to Sony’s online store. Other Square Enix titles such as Crisis Core: Final Fantasy VII and Valkyrie Profile: Lenneth are also not available as PlayStation Network downloads.