Further details from Famitsu.com:
http://www.famitsu.com/news/201412/18068176.htmlThe project is now named "Play,Doujin!", with a new URL:
http://playdoujin.mediascape.co.jp/A fourth title has been announced: "Gensou no Rondo" by CUBETYPE.
Two Vita themes are released at the PS Store, each at JPY 432, one for Gensou no Rondo, the other being 幻想郷四季・冬 "Four Seasons of Gensokyo - Winter". The latter is part of a series to be released over a year, featuring contributions from fan artists.
At present, the two RPG titles are supposed to be released on Vita, while Gensou no Rondo will be for PS4. The platform of Sky Arena is still undetermined.
Well, from a technical perspective, it's only natural to forego supporting PS3, due to how difficult it is to develop for. However, the adoption rate of PS4 in Japan is... still far from optimistic.