shmups.system11.org

I've been watching some of Kamui's replays and there is a section on stage 5 where she sometimes milks two planes which are circling around her. Pretty awesome stuff.

But why does she stop milking at some point? Is it because of the frame rank? It looks like she could counterstop the game if she's just patient enough. There shouldn't be any timer because it's not a boss fight. I also don't understand why she doesn't perform the milking on every run. Are there any hidden mechanics that prevent her from doing this?

edit:

You can see the trick at about 19:10.
https://youtu.be/VisS7_ROmYw?t=1135

It's been a while, but my recollection of this is:

If you do it for too long, Black Heart becomes invincible and never times out or something. The reason the game isn't officially score tracked anymore is because of this trick though; if you get just the right timing Black Heart will still be destructible but doesn't time out, which you can use to milk the boss until you decide you've had enough. That said, rank still ticks, so doing so can make the rest of the game absurdly hard if you go for too long.

Wow, now that's a pretty weird exploit. Thx for the reply. These old game never fail to surprise me.