Thanks for playing the game!
I also see that for many people the grindstone was a bit harder than I anticipated. I guess this is what happens when you test a mechanic over and over again so you learn it a bit too much.
I mean the grindstone was fine, what i THINK was happening (correct me if im wrong) is it was remembering my ridiculous shift from my first attempt and carrying into my next go as if I started off by holding down an arrow full force xD I do believe it was 100% user error because after I got the first one going correctly the other was easy.