Hello ryu sei~ 🥳 I think this diff needs more variation and making the notes a bit spaced out, it feels too claustrophobic for me since some of the section has notes really close together compared to the higher diffs, you can still make the notes spaced out from each other and still make it easy by having them in the same row on your keyboard.
Though some of the section have the notes too spaced out which makes them harder to read.
I'll start by having some examples on what can be improved (feel free to reject these suggestions):
00:03:091 (3091|5,3488|10) - Moving this to the top row will make this part easier to press since they are on the same row.
00:08:654 (8654|11,9051|4,9448|12,9846|3,10442|11) - this part is a bit too close together for me, you might want to space them out by moving 00:08:654 (8654|11,9051|4) - to the bottom row and moving 00:10:442 (10442|11) - as well
00:13:422 to 00:31:700 - You could probably make this section better by moving around the long notes a bit, you can have move them to different columns but on the same row and it would still be easy to press.
here's an example on 00:13:422 to 00:18:985
and an example on 00:26:137 to 00:31:700
discussion about this is continued in a VC...