A super cool guy reverse engineered Ketsui and made his own arrange mode and released it for free. It is available here.
The really cool news is that you can play it on an actual PCB! I had been thinking about getting an EPROM programmer for a while, but this pushed me over the edge and forced me to actually get one so that I could burn a copy of this and stick it on my Ketsui board.
This is my first programmed EPROM, a 27C160 which is what Ketsui uses to store its game logic.
I haven’t played it much yet, but it is really well done and is a neat take on the original game. Basically, you hold down A+C to jack up the rank (a la Dodonpachi Daifukkatsu Black Label) and then you get bombarded with the bullet patterns from the more difficult 2nd loop of the game. You can let go of A+C to drop the rank down and make things easier, but of course you get more points by making things hard for yourself.
So far I’ve only been able to reach the 3rd stage on one credit, but it’s fun to get the rank high and see how long you can survive. I probably won’t play this super seriously, but it’s cool to get a new variation of a game I love for free!