In an Iwata Asks interview, Hitoshi Yamagami explains Zangeki no Reginleiv was in development for over three years.
Sandlot’s first Wii game got approved between the summer and fall of 2006, even before the Wii was in stores. Zangeki no Reginleiv finally comes out in Japan next week on February 11.
The interview also mentions there was some debate about the level of violence. In the end, the development team came to a consensus that chopping limbs off was OK because it was against mythological giants and not people. Zangeki no Reginleiv is Nintendo’s first CERO D (think ESRB M) game in Japan. To prevent parents from picking up Zangeki no Reginleiv blindly, Nintendo decided to pack it in a different colored box. Now all Wii games rated CERO C and up are in black boxes.