There are something that you have to remember when you are playing the special difficulty chart.
In the middle of the song, the middle brick red note lines will keep falling mainly hold notes and slide notes, which seems to be impossible to tap those with two fingers. However, they can all be hit since there is overlapped space in all note lines in the middle.
However, when tap notes are falling, there is no overlapped space.
Near the end of the song,a hold note is hidden in the solid black note lines.