This is a pretty nice twist on the theme!
I like the idea of swapping perspectives from runner into bullet hell, but it was a little inconsistent at times, where I felt like it transitioned sooner on certain runs, and I lost a run to bullets spawning while the camera was transitioning out of the bullet hell phase, since I wasn't expecting the bullets to still keep on their trajectory despite the perspective shift.
I do think the upgrades should use a bit of tweaking - the speed boost really does just feel like a threat, which is fair, but the fact that the slow time grays out the entire screen means you can't tell what you're going to be picking up, so its safer to just avoid everything. If the different powerups had different particle effects, I think that would help alleviate the issue.
Also it slows everything down, including your attack animation, which can just make the already pretty precise timing even harder to nail.
Maybe it was a hold over from planning, but once you defeat Shiori it just keep going, which I think is fair, but also there's not much else to do but run, so I feel like it might just be better to end the run there, until more members are implemented, and maybe it could be like a boss rush
But all in all a cool submission, and the music and SFX were really good, great work!