Project Siren is a video game development team that works within SCE Japan Studio. It is best known for the survival horror series Siren, released for PlayStation 2 and PlayStation 3. The team is conducted by game designer and director Keiichiro Toyama.
Following development on the Siren series, Project Siren began development on Gravity Rush for the PlayStation Vita, which was released throughout various regions in 2012. However, on the 19th of September 2013, at the TGS in Tokyo Japan, Team Siren released a trailer for a brand new instalment in the Gravity Rush saga most likely to titled Gravity Rush 2 at its official unveiling. Towards the end of the trailer, the words "A new project from Team Gravity", can be seen, and so it seems as though Team Siren have re-established themselves as Team Gravity, changing their studio name to reflect the development of their new IP. More: en.wikipedia.org.