In the most recent Chuunibyou Radio nicodouga livecast they showed part of the PV of INSIDE IDENTITY and some kind soul had crop out just the PV section.
So in the end to make the PV they had a budget of 1 million yen, which the cast won from the various games and challenges from the previous livecast, and they also include some of the ideas proposed by the seiyuu themselves during the past (IIRC the 3rd) livecast. Having a battle was a popular idea and sure enough they have it here between Chinatsu (Shinka) and Sumipe (Dekomori), the transitions between the real world and imaginary world battle is a nice nod to the anime too. Anyway see for yourselves, enjoy.
EDIT: The PV is self-produced by the cast and a DVD of the full version plus making of footage will go on sale at Winter Comiket
EDIT2: Have to say I'm greatly amused by the return of Sumipe's DFM costume