I just tried Ikaruga as a Dreamcast game in the Demul emulator and it had a strong vibration by default. Then I tried the arcade CHD version and it doesn't have any kind of vibration on my Xbox 360 controller, do you know if there's anything one has to configure in order to have this kind of feedback in Naomi games?
I was more interested even in having some kind of rumble in driving games like the Initial D series in the Naomi platform... preferably on a driving wheel, but failing that even on a controller?