As reported last night, Senran Kagura Burst: Crimson Girls will include both Crimson Girls as well as the original Senran Kagura: Portrait of Girls on the same cartridge. You may recall that the original game was lacking in a few areas, such as the locker room—which is where you select your costumes—only being playable in 2D. This is being retroactively fixed in the Burst version, along with other tweaks that are present in Crimson Girls.
As detailed in the past, Crimson Girls itself is a sequel where you play as the opposing faction of ninjas. They’ll have new costumes, and screenshots from Famitsu.com (NSFW) show Hikage in a maid outfit and Homura wearing a plain white shirt. Marvelous promise a large number of costumes for the sequel.
Senran Kagura Burst: Crimson Girls will be released in Japan on August 30th.