Ten years have flown by like an arrow. It seems there have been a few discoveries in Kirby's Dream Course during that time, and just a few days ago, a simple new discovery became a hot topic in the Japanese community.
Here's the cool new find: Kirby slows down ever so slightly each time you press the Y button while he's rolling.
It's the total opposite of the A button's "Go for it," so folks are starting to call Y the "Don't Go for it."
https://x.com/hal_tsuki/status/2008915675730129278
Koten/紫雨陽介 (Murasame Yosuke), famous for his deep dives into KDC physics, has started digging into the game and figured out that the Y button temporarily increases the friction coefficient.
https://x.com/Koten_U/status/2009598420349255765
https://note.com/yosuke_murasame (Explanation of tons of KDC mechanism there, in Japanese)
More details might come out bit by bit.
Edit:
https://note.com/yosuke_murasame/n/n9223b8acd01c