Get ten consecutive golden notes without failing a single note in between them. Don't play a note while it is in the green area or it will break the combo.
Try getting ten red notes in a row without interrupting it with another color. This will earn you a 2,000 point bonus. If you get ten red and blue notes in a row without missing or getting green notes, you will receive 1,000 point bonus. If you get a green note it will ruin your current combo.
"Saviour of Humankind"
Simply complete the game under the Hard difficulty setting.