There are more skimpy costumes, more fabric-destroying attacks, and a much needed graphical overhaul. But the real new features are the co-op and tag team modes, allowing you to play with others through your fan-service infested adventure.
For those not acquainted with the niche, Senran Kagura is a 3D hack and slash game series involving two rival female ninja clans, who are under the guise of high school students. All of them have a knack for losing their clothes and having over-sized chest areas.
While Senran Kagura 2 is expected to release in Japan on August 7th, no North American date has been announced. The title is a Nintendo 3DS exclusive, though a cooking-game spin-off is coming to the PlayStation Vita. You can read the review of the first game here.