How To Full Combo YuMei
Things to consider when trying to get all perfect notes
Make sure that Yu's bar doesn't go all the way down, if her bar is all the way down, you will automatically lose.
Use one hand to hit the notes and use the other hand to switch between Yu and Mei, for example, your left hand is hitting Z and your right hand is on the middle mouse, trying to switch between characters using one hand throws you off.
Use drinks to your advantage, The YuMei drink (i believe) makes it so only 1* modifier will show up, if not, Pica and Toto's drink help the perfect hit time as well as effectiveness.
Make sure that you don't go over any of Yu's curses, wait until you're at a comfortable perfect hit rate, then start claiming the Blessings to get rid of the curses.
If you have the Lucky Charm, make sure you choose the mirror first!
When trying to complete the YuMei challenge, the one modifier you want to focus on is mirror, mirror is the best safeguard to make sure that you hit perfectly every single time.
As stated above, you always want to make sure that Yu's bar doesn't go anywhere that is dangerous, you will naturally win the game as every time you finish with Mei, your multiplier will go up every time.
Which modifiers should I prioritize first?
Mirror - Increases the perfect hit size.
Perception - This makes it so that every time you hit a perfect, you will gain a critical which will make you finish faster.
Stamina - Yu's bar will de-progress slower when you focus on Mei's side.
Needle - Makes you finish faster every time you hit a perfect note.
You also want to make sure that you don't claim any of Yu's curses, in doing so, it makes it much harder as some of her curses will make the challenge MUCH harder, keep her bar to a point where she doesn't use a curse and to the point where she won't immediately fail you if you let it drain too much.
Eventually, if you do everything correctly, you will hit all perfects and eventually full combo, you can also spam rerolls and whenever you run out of money, go to the haunted hall and complete it for more Rep. (doing this will not remove and drinks)
This is the most tedious step in the game, but it'll be worth it!
Source: https://steamcommunity.com/sharedfiles/filedetails/?id=2924087345