Some density concerns throughout the set, as follows:
Kantan
00:05:777 (6,7,8,9,10,11,12,13,14,15) - I like the idea here, but without a substantial break beforehand this seems tricky for the difficulty level. You could either rework the start slightly to accomodate a 4/1 break by, for example, placing a 1/1 5-plet between
00:01:604 (1) - and
00:03:690 (3) - , or you could try a different, more linear rhythm to remove this issue.
00:12:038 (15,16,17,18,19) - the 3/4 over notes 16 and 17 should be followed by a 2/1 break, since this rhythm is considered complex for this level. Removing
00:13:604 (18) - would be an ideal fix for this if you want to keep this rhythm, if not you can move
00:12:951 (17) - on to the white tick and adjust colouring.
00:21:430 (29) - Remove this note to create a 4/1 break in order to comply with the ranking criteria.
00:22:473 (30,31,32,33,34,35,36,37,38) - same issue as
00:12:038 - , but if you want to keep this rhythm then removing
00:24:038 (33) - and
00:26:125 (37) - would be ideal.
Futsuu
00:03:690 (6,7,8,9,10,11,12,13,14,15) - This amount of 1/2 followed by 3/4 could be quite tricky at this level. Removing note 7 would resolve this issue without removing too much from the rhythms represented here, however a 2/1 break would be necessary afterwards, which can be fixed by removing
00:06:299 (13) - and
00:06:560 (14) - , placing a don at
00:06:821 - , and changing
00:07:082 (15) - to a kat. The colouring doesn't have to be as I mention, but that feels the most correct for following the drums.
00:17:777 (41) - and
00:26:125 (62) - Remove these notes to create 2/1 breaks in order to comply with the ranking criteria.
Muzukashii
00:01:604 (1,2,3,4,5,6,7,8,9,10,11,12) - the 1/4 2-plet followed by the 3-plet with no substantial break between may be a challenge for this difficulty level. Removing the note at
00:03:430 - would resolve this issue without removing too much from the rhythms represented here.
00:14:125 (45,46,47,48,49,50,51,52,53,54,55,56,57,58,59) - these 1/1 break timings are quite unconventional, and while they do follow the ranking criteria, I feel as if this section could be adjusting slightly to allow the breaks to rest at more conventional points of the songs. The first half of this would follow similarly to the rhythms at
00:18:299 (59,60,61,62,63,64,65) - , but with the inclusion of 2 notes at
00:14:386 - and
00:18:560 - . This would also involve removing
00:15:951 (51) - to create the desired break, and you could also add a note at
00:17:256 - for better flow. If this is slightly confusing feel free to shoot me a message and I can elaborate further on this.
00:24:560 (80,81,82,83) - Suggestion: I prefer following the sound of the saxophone here as it's the more prominent instrument in this part, so moving
00:24:821 (81) - to
00:24:821 (81) - would flow nicer.
00:27:951 (92,93,94,95,96,97,98,99,100,101) - Suggestion: You could make a slightly more interesting ending by removing
00:28:473 (94) - and adding a 1/4 3-plet of kats at
00:29:517 (99) - .
Oni
00:01:604 (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20) - Starting at this density here may be a bit much, removing
00:03:430 (10) - would resolve this issue.
One final suggestion: consider increasing the OD values for the Kantan and Futsuu by 1, to create a more linear trend between the difficulties.
Sorry for yapping, I hope this feedback is useful to you!