Are you sure it's actually in Japanese? I'm just looking up the game on Youtube and all of the menus are in English and the ending text is also in broken English. I don't know if this had a translation to English or if it's supposed to be like that, I've played some Japanese games that were entirely in English so I'm thinking it's possible.

http://www.youtube.com/watch?v=vLNYm9p4WyE