It will finally be presented at the Cave event on the 23rd this month. A promo movie is already on Arika's website (Download, 38MB). You can also post questions to Ikeda and Mihara regarding the game on Cave's site (see first link above, deadline is Thursday 13th).
That looks sweet, but wasn't Ketsui the game that Cave was going to port to PS2 but cancelled it because there was one part that had too much slowdown? If there's slowdown on a PS2, then how could it possibly work on DS?
There are discussions going on in the shmups forum. Apparently Cave said that a direct port (emulation?) to PS2 would be possible. The DS version is a redesign anyway and not an attempt to reproduce the arcade Ketsui. Maybe the Cave/technical experts can elaborate on that?
This is not Ketsui. It is Ketsui Death Label (working title). As far as anyone can see, it is a highly tweaked (and watered down) boss-rush version of the game with a highly altered score mechanic (you don't get nearly that many point chips on the bosses in the real game).