Blushing wrote:
Silver S/SS are awarded only for a true modification of how the game is seen. I'm not sure if there is any particular reason why they are that way other than HD and FL are unique in how they change the map - so therefore they award a unique rank.
WEll, if you think about it, the most that HR or DT does is either increase the AR/CS significantly or just speed up the song. It's not affecting your ability to see the notes that are either arriving or already on the screen, just your ability to react to their appearance. That is just a test of your reaction time, basically.
HD and FL, however, do affect your ability to see the notes, as would Fade In. Hidden actively hides both the Approach circle and the note itself, Fade In is essentially the opposite (inverse?) effect of HD, and FLashlight is, well, Flashlight. What they share in common is that they directly affect and inhibit your ability to see notes that are on-screen. It's not just modding how you react to the notes, but how you remember where they are, where in the beat they fall on, etc.