- there's the original HDN that started it all,
- then came a continuity reboot, MK2,
- and there's a sequel to that reboot, Victory (V for short).
- Now, the latest sequel, VII, is in development.
All of which are for the PS3, I believe. Now, in addition to the main timeline, there's a so-called "Re;birth" version of each, meant to be remakes of the first three games, available on the PS Vita.
Then, there are three spin-offs of this series, which are:
- an idol raising sim, Producing Perfection,
- a hack and slash, Chou-somethin' Neptunia U,
- and a... What's it called, an SRPG? It's the one featuring Noire/Black Heart, right?