and why not? who says Zoonami have to conform to what the industry standards are? i say let them be secret, just think, the majority of bad impressions come from early screens/videos of games, mario kart was attacked for being too slow, Wind Waker was slaughtered online because of its graphics, further along in the developement process and Mario Kart's speed issues have been adressed and is now sufficiantly fast, and well.. personally i never had anything wrong with the wind wakers engine, but now most people have played it either enjoyed it or found it too short/easy, only a few still have a problem with the graphics it has.
basically, Zoonami should release screens when they are damn well ready, when the game is near completion.