In this forum thread, CRV of the Game Developer Research Institute has announced that he has been talking to Tsunetomo Sugawara, a former employee of Hertz who has been character designer for their famous platformer Psycho World. Parts of the interview that have been translated already can be read here. If you can help with the translation, or if you have any questions you'd like to ask Tsunetomo, you can do so in the relevant forum thread!
Relevant link: Hertz interview