Hey, thanks for all the feedback and creative ideas! All of your proposals are pretty cool! Especially the glass filling animation makes much more sense now that I think about it which would definitely get rid of the memorization aspect of the game.
Regarding your question, I can do the fast portion about 70% of the time. The important part is to do it in a smooth motion and abruptly stop before repeating said pattern until the end. If you truly insist on it, I can record a video showing you how I do it :P
Also regarding hit error, It was something I planned to add, but sadly had no time left, which contributed to the difficulty significantly. This lack of time is also why the song cuts off abruptly.
Another reason is the fact that i took myself as a the basis for how hard the game should be... that was probably a mistake on second thought.
I would consider myself quite good at rhythm games, so with the combination of me wanting to make an S rank quite hard to achieve it all lead to this outrageous difficulty.
I don't really get what you mean by the fact that the music tells you when to move? Sorry about that, further clarification would be appreciated!
All in all, thanks for your comment, all the feedback definitely helps a lot! Hope you had fun whilst playing my game :)