Up to the orange squares, I thought the precision was hard-but-fair. There's a surprising amount of subtlety in the controls and I was eventually able to make my ascent largely repeatable. With that said, I do think you should offer a way to survey the pachinko-style drop that precedes accessing the entrance to chapter 4, otherwise the randomness of your first interaction with it just feels a bit unfair.
Once I got to the orange squares, I just found it impossible to get the timings repeatable. To the point that I'm wondering if the precision required is either outside of my physical abilities or outside the technical limits of puzzlescript on OSX Chrome. I ended up screencapturing that section with my inputs displayed on screen and hit the first tricky part once in 8 or so attempts. Looking at the inputs frame by frame, I can't really see what was different about the time that worked.
All that said, I thought this was v cool and was technically impressive :)