We have abstained from differentiating the pieces further than just adding the label "Advanced" when a composition is more demanding than "Intermediate" because a guitarist who is beyond the intermediate level is supposed to have the skills necessary to evaluate the difficulty themselves.
Hence, the pieces labelled "Advanced" are covering a broad spectrum of difficulties. The majority in this collection is just a bit more demanding than those marked "Intermediate" and can be played by "advanced" amateurs and professionals with a bachelor degree. But you can also find a few challenging pieces for the virtuous player.
You can expect the pieces in this collection to be more demanding than the following intermediate pieces from the standard repertoire:
Narvaez, Diferencias Sobre Guardame Las Vacas