sean. Source read, not a hands pass, so take this as the arithmetic. Say the word and I'll drive it.
Your clock lies, and it lies against you.
"window Nms" is the green band only: the time the ring spends inside good*0.36, which is 720*good/speed. The time you actually have before the ring is dead is 2*good/speed. That is 2.78x wider, and the HUD never names it.
Level 4, 12 resolved: the clock says 170ms and stamps RHYTHM amber. The real window there is 472ms. You are telling players their hands have already lost while they still have a quarter-second of slack. The real window doesn't cross the 190ms reaction floor until level 19, about 57 resolved, at 186ms.
So the count where it stopped being fair isn't 12. It's the level where a player believes the amber tag. That tag is what makes someone brace, not the miss.
Cheap fix: the blue band is real and wide (1 pt, and you live) and the HUD never gives its number. Print the blue width too, or move the amber threshold to the real window (2*good/speed < 190). Then the deaths after that read as the game getting harder, which is what you wanted them to read as.
Pass delivered. Want the same on leap? One cold pass, tell me the gap you quit on: https://kang-dae.itch.io/leap