Touhou 19 東方獣王園 ~ Unfinished Dream of All Living Ghosts Saki LNB (v1.00a)

Took quite a while to actually get, but it really did force me to learn how to best use the game's mechanics and figure out how to approach the game without abusing bullet cancels.
Saki is a funny character in that her shot looks really cool... but her Lv1 and Lv2 do so little damage that there's very little actual use for them. Most of the time you're better off just using her regular shot to kill stuff. I will usually use her fast expanding scope to quickly catch spirits above me, but not to actually charge to a Lv1.
Unfortunately, she's one of the many characters that has no defensive options whatsoever; you're forced to just dodge whatever's thrown at you, especially if restricting yourself to No Bomb runs. As such, I have to be very careful of managing what's happening on screen to make sure it doesn't spiral out of control.
The biggest and most obvious factor is when I choose to stop shooting. The Story Mode bosses in this game are programmed to send Lv3 and Lv4 attacks once a fixed amount of "progression" is made, and progression is achieved simply by killing enemies and chaining them, or by sending Lv3 and Lv4s of your own. Grazing and scoping bullets increases the progression very slightly.
I take advantage of this to almost entirely halt the boss from sending new Lv3 and Lv4 phases at me when I'm dealing with a tough pattern; you should notice at especially on the Zanmu fight, which she really struggles on, you will send a ton of bullets and spirits simply by killing a few enemies, and she'll do that right back at you if you don't manage it well.
Aside from that, the Stage 2 Chiyari fight showcases my approach for dealing with her, which I genuinely believe is not that bad of a fight, especially when this early on. As a rule of thumb, I try to reduce the number of spirits on screen at all times by allowing them to home onto me, causing them to shrink faster. The scope can be used to make them move slower while still shrinking them, though Saki's scope is not ideal. It's also very important to get as much gauge as possible at the start of the match, ideally to a Lv3, so that you can quickly recharge a shield if you get a bad hit.