Just going to be providing general feedback for this one, since I feel I'd probably be highlighting about 80% of the notes for suggestions. (Sorry!)
Not a fan of LNs (long notes, which for some reason are classified as sliders by the client), myself. But it works for the most part I guess? The trouble is here, with such a large amount of LNs for a difficulty like this, the playfield can get a little cramped and things can be hard to read, which is certainly an issue here at times, like 00:25:423 (25423|3,25423|1,25423|2,25561|2,25561|1,25561|0,25698|1,25836|2,25836|0,25836|3,25974|1,25974|3,25974|2). Take this into consideration when testplaying (which you should probably be doing, as well as asking others if you can.) and making changes.
The other thing with LNs is properly positioning releases. The most widely accepted method is to have them end at the start of something else, so that they're easy to time. However, sometimes finding somewhere to properly end the LN conveniently isn't possible, or for playability's sake, like around 00:52:128 (52128|2,52265|2,52403|1,52541|1,52678|3,52816|3,52953|0,53045|2,53137|0), you're better off with using SNs, which carry across the same message.
Of course, emphasis layering and consistency is still something that needs considering here. Generally speaking, at this difficulty, we're looking at using doubles for bass kicks, triples for snares and triples for crashes.
Stacks: Unless for a gimmick effect (which isn't really here), having too many consective notes in one column can be a bad thing, as it can put too much strain in one hand. Usually, the maximum length people find comfortable is a stack of 3. So things like 01:01:488 (61488|0,61626|0,61763|0,61901|0) may need rearraging to avoid a stack that's too long. This is often tied to ignoring a column for too long, so make sure notes are fairly spread across the columns.
Other things that I don't know how to categorise:
- 00:08:694 (8694|3,8997|2,9072|1,9148|0,9603|0) - I know what you're trying to do with here, but with the sound being so erratic and seemingly random, I think you'd be better off mapping with the single LN like in the other difficulties.
- 00:55:156 (55156|0,55202|1,55248|3,55294|2,55339|0,55385|1,55431|3,55477|2,55523|0) - Another erratic sound that is completely unmapped in the other difficulties, I'd simplify this down quite considerably. The other alternative is to delete that section entirely and leave it unmapped like the other diffs.
- 01:04:516 (64516|2,64516|0,64585|3,64585|1) - This is one sound, so why there are two seperate chords for it is a little confusing.