I really like how those crystals have a reflection in the mirrors in the background.
The 3rd room requires 4 of those mid-dash walljumps in a single sequence. It took me like 100 deaths before I could even do the 2nd dash-walljump somewhat consistently... the 4th one has a really tight window and then you have to react really fast right after that with the red bubble stuff. At least the part at the end where there's like 5 dash crystals and some dash switches to open doors, that part isn't that hard so once I got in the rhythm of doing the early part consistently, I was able to do the rest of it and beat it in under 500 deaths.
Chapter 6 C-side
More mid-dash walljump shenanigans, only this time with those bounce pad circle things... and then the 3rd room is a really crazy long room that starts with a spike pit drop, and then it's like I don't even understand how you're supposed to do it. It looks like there should be a feather at the bottom but it's not there?
Okay I get it... you actually need to bring the thwomp with you all the way down. That wasn't actually that bad... and it gives you another checkpoint half way through the room so that crazy bounce-pad hell at the end is its own thing. Beat it in under 150 deaths.
Chapter 7 C-side
Wow, the first room of Chapter 7 C-side requires 7 mid-dash walljumps in a row... well actually it wasn't that bad, since the upward wind current in this room slows your descent making it way easier to line up your jumps.
The 3rd room is just insane... it took me so long, I was sure I'd get like over 1000 deaths in this level, but since the room is very long and I got to the point where I could consistently do the first part without dying, it was actually much fewer deaths than it felt like. I beat the level in under 450 deaths...
Now there's just 8c left... god damn I can't even imagine how crazy it must be. 8b was already a nightmare.