Thank you
I developed a difficulty measure, with colors and numeric values. with an image:
Very easy means that the game can be played by anyone and can be completed without a lot of effort.
Easy means that the game can be played by anyone and probably the game will need some effort to complete, but all players probably can complete it.
Average means that the game will require some effort to complete and no all people can complete it, but if you practice, probably you can don't matter who are you or your skill.
Hard means that the game should need a lot of effort to complete and probably will cause some frustration, will need some retries in each level but probably completable for experienced users.
Insane means that the game should need a lot of effort and time to reach the end of it, as the player will retry very often each level to complete it and probably completable for very advanced users.
None means that the game has no difficulty itself, as it is a simulator, an animation or there is not a specific objective to achieve.