Dunno but there must be something when they're going so far to hide it.
You mean like how the location and time for the preview screenings are top secret, and only those selected get the info in their acceptance post card?
Or the character designs being kept completely under wraps until the day it airs?
How about the secret vocalists for the opening theme which will be revealed whenever they decide to?
I think it's just a super hipster production, just like how Penguindrum never had a full PV or real story description until the show actually started airing.