Difficulty

Difficulty is a selection of levels that the player can either choose or is set automatically. In GH:SE, difficulties for songs that are not customs have a hard-coded difficulty value, meaning it cannot be modified without hacking.

The difficulty of a song is defined in the number of stars the player sees in the song stats on the song selection screen (either Cakewalk, Easy, Medium, Hard, Insanely Hard, Master or Impossible).

When a player makes a custom song (in V9), they can set the difficulty of their song by giving it a number from 0 to 6.

Cakewalk ( 0 )
Cakewalk (light-blue with no stars) goes to the easiest songs that take no effort to completely master.

Easy ( 1 )
Easy (green with one star) goes to the slightly easier songs that take a little bit of effort to master.

Medium ( 2 )
Medium (yellow with two stars) goes to songs that have very little hard parts. Mastering songs with this difficulty can be tricky.

Hard ( 3 )
Hard (orange with three stars) goes to the songs that have infrequent easy parts (little to no Star Power). Unless you're good at the game, mastering these songs is almost impossible.

Insanely Hard ( 4 )
Insanely Hard (orange-red with four stars) goes to songs that are not easy in any way possible.

Master ( 5 )
Master (red with five stars) songs are complex with almost non-stop fast notes.

Impossible ( 6 )
Impossible (pink-white gradient with five glowing stars) goes to songs that nobody will ever complete (mostly Go Crazy is associated with this).

Undefined ( ? )
Undefined (no stars) only goes to songs that are a work-in-progress.

Trivia

 * So far, there is no song in the game that has a higher difficulty than 4 (Insanely Hard).