Cave is best known for its crazy shmup arcade games. A spate of them are getting released on the Xbox 360 like DoDonPachi Dai Ou Jou Black EXTRA and Ketsui ~Kizuna Jigokutachi ~ EXTRA.
Thing is developer 5pb has been doing these ports — and not doing a very good job. DoDonPachi Dai Ou Jou Black EXTRA is so buggy that sales of the game have been halted in Japan.
Ketsui ~Kizuna Jigokutachi ~ EXTRA, likewise, seems plagued with problems. The game was originally scheduled for release on May 28 in Japan, but according to a recent Xbox Japan press release, the game is now TBA. The 5pb Games page also lists Ketsui as TBA; however, the game's actual page still carries the old release date.
There is an upside. Cave, not 5pb, is porting Mushihime-sama Futari to the Xbox 360. THANK GOODNESS.
Xbox 360® 向けタイトルラインアップがさらに充実 [Xbox Japan]