00:31:561 (3,1,2,3,4,1,2,3,4,1,2,3,1,2,3,4) - this is a very long streak of notes with no breaks, which could be straining to a player of this level
i'd recommend just deleting 00:33:304 (4) - and 00:34:853 (4) - so that the long streak is split up evenly without losing too much active playtime
00:36:593 (1,2,3) - you could possibly also make these 3 sliders just 1/2 sliders, so its not confusing for the player
01:25:756 (3,4,1,2,3) - this is currently very sense dense playfield wise, mainly due to the overlaps being done here, which could make it confusing to play for players of any skill
to fix this i'd recommend:
01:38:530 (1,2) - any reason for not stacking this like you've done for other 1/2 gaps? its ok just curious
01:44:723 (1,2) - would make this 3/4 sliders to represent background melody, like you did 01:46:272 (1,2) for example