It seems like the new Gravity Rush project is actually a Playstation 4 port of the original.
A rating for Gravity Rush Remastered has surfaced on the Korean Rating Board, for Playstation 4. As the rating implies, this is most likely simply a remastering of the game, with improved assets and performance on the Playstation 4.
Despite a hopeful teaser trailer, the platform and conditions for the new Gravity rush project is still unconfirmed. For now, we’ll keep you guys posted.