Thanks so much for this link!
I never heard about it before!
I applied the patch to a USA ROM and it seems to be worked.
Are you sure it requires a JAPAN ROM?
It came from a Japanese site which they used the Japan ROM, not sure if there are any real differences though between the both of them. I was hoping the author of this hack would take advantage of the updates this patch provided though
Regardless I am looking forward to this when its done! Gradius hacks are always good!