HD is often easier on lower ARs (like AR 8 or 9) because the circles stay on screen longer before vanishing, making the rhythm more intuitive.
Below is a short, rhythmic piece written from the perspective of an osu! Hidden player. The Invisible Ghost PLAYER 1 HD
If you are actually looking for a "good piece" (as in a ) to play as the HD player, look for maps with these characteristics: HD is often easier on lower ARs (like