Additionally to what everyone posted:
[Gift]
The spread inside the difficulty itself is really inconsistent. The beginning and, specially, the first Kiai, barely plays like something above 4,5* whereas in the other kiais you have huge jumps, huge SVs (for example: 01:52:676 (3,1,2,1,2,1) - 02:01:592 (1,2,1,2,1,2,1,2) - ) that compared to the first one you have lower SV and lower jumps (for example: 00:54:233 (1,2,3,4) - ). It happens throughout the entire difficulty but it's really noticeable in the beginning.
I know this is a huge collab and such but It's not really an excuse to make things inconsistent in terms of difficulty spike. Everyone has their style but that doesn't mean they can make something really easy and then someone else makes something extremely hard for the same section.
I can't really think about anything else other than rework most of the patterns in a way that intensity feels as equal as possible between the mentioned parts. Definitely increasing the SV is a nice idea and you have a lot of spots like 00:50:554 (2,3,4) - 00:52:252 (3,4,5) - 01:06:120 (1,2,3,4) - to buff a little with some circle jumps, instead of low SV sliders.
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If something felt questionable, feel free mention it.