I really liked the aesthethic (both graphic and sound). And actually, i don't have a lot to say, because it's good at what it does. If I could make a suggestion, I'd love to move and sync myself with remnants from the past/glimpses from the future to explore a bit those echos. Actually that would make more notes to write but as a counterpart, you would be able to have them suggest instead of writing the emotion of the character.
On the technical part, it's already been precised but feedback is important for when you manage to get a note (maybe just pause the game, small animation and show the text). Finally, at least for the mouse control, if you press both input (left and right), you manage to get in the "time-travel" state without pushing any button.