i gave up playing this game, it's been 2 months but i watched more gameplays about this.
To be honest, I'm not good at puzzle (very dumb at puzzles) and i need to watch walkthrough just to get an answer. But i did like the game for some reason although i kinda didn't get the puzzle just to figure out how the manual works.
I did watch the ending. I kinda have a headache to this when i tried my best, it's still very challenging. Other than that, have a great day!