Arrghus

Pinkus - Yesterday at 10:39 PM
1. Dash into the room always (ofc. it's the fastest way to do pre-arrghus), so that your sword is already out.
2. Hold B entering the room. Press Y+A on the same frame. You can walk up a tile before doing this.
3. Hold <^ right after you item dash.
4. If you get the item dash, the first puff will die instantly, as you're walking <^.
5. Watch your sword as cue. When it starts to wiggle, repress Y. I think it's 3-4f window to repress Y every time.
6. Keep doing this for 4 Y presses total (including the initial Y+A).
7. Now you need to walk backwards a bit, because Arrghus is getting too close. So hold v> after 4 puffs are dead.
8. Keep doing this, but alternate v> and <v.

Addendum:
1) If you mess up #8 above because Arrghus literally runs into you, it is because you didn't adjust to his speed. In fact, there is no formula for 0 cyc. You actually need to adjust to the rng. If he comes at you fast, you might need to hold v instead of v> or <v. No tutorial can really teach this, and it's just a product of doing it many many times.
2) If you mess up anything because your hook went the wrong way, your timing was off. You need to repress Y in a timely fashion. So that's what to concentrate on if this is your problem.
3) If you do get hit because he goes aggro, try to quckly get to his right side, and slash your sword (and hold B) and redo the Y+A from the right side instead. With the proper technique this should work  maybe 30% of the time.
4) There are more movement patterns than what's outlined above. Some people like to move up 3 tiles before doing the first Y+A, which will end up changing #4-#8. Watch top players to see different movement patterns.

Pinkus - Yesterday at 10:42 PM
Big picture: The outer circle of puffs will move clockwise, while the inner circle of puffs will move anti-clockwise. This is the main reason why alternating v> and <v is important. Or at least, it is very important to know that your goal here is to remove the ones that will soon be at the front (thus being more likely to hit you)
That last part is more advanced but it's important so it's something to have in the back of your head as you practice
It will eventually change your movement pattern depending on how it all unfolds (you might do 2x v> instead of alternating, or maybe hold straight v instead etc.)
There's also a lot of pattern recognition here. And again, I don't think a tutorial can truly explain it. You just have to do it again and again, and eventually you will recognize patterns where "if I do this, it usually works". This is the 2018 meta anyways. I still think it should be possible to do arrghus 0 cyc 100% of the time, but I don't think anyone know the technique to do that atm.

josh - Yesterday at 11:44 PM
another reason you want to kill the ones that are low is because by the time he's at the bottom of the room, low puffs can be difficult to kill in general, because you're not able to pull them far enough away from arrghus
so they stay invulnerable

Pinkus - Yesterday at 11:45 PM
yeah that's where pattern recognition comes in
you'll just know that killing the bottom left ones first is the right choice etc.
but honestly no way to really explain this in text
super advanced (stuff I struggle with) some puffs can be grabbed while you're not even close to being below them, and that's kinda important to do sometimes to save the 0 cyc(edited)

josh - Yesterday at 11:46 PM
yeah imo just work on the technique first, and then once you can do it, just really start focusing on your kill order
and focusing on how he moves
because those two things are what really improves consistency