The author has updated his blog, saying something among the line of "you'll be surprised if you only know comedy-Shinbo", "An approach in this series is totally different from what you seen in Sayonara Zetsubou Sensei" and "I'm Shinbo fan after all (lol)". The PV is total of full two minutes.
Sendenman blog also write "there'll be blood, action and nude scene".
Can I take this as Shinbo going back to his former style?