Difficulty levels vary from 1 to 9

Very easy
Simple melody and bassline; No position changes on the keyboard.
(Accessible from the very early stages of training)
Very easy
Simple melody and bassline; Very few position changes on the keyboard.
A few passing notes.
Simple melody and bassline; Position changes and passing notes more frequent.
Faster with more rythmic difficulties
Chords make an appearance (left hand), as well as triple time (transcription depends on arrangement).
Left handed chords more frequents. Use of the resonant pedal.
Medium tempo
Quicker tempo, with a more advanced piano playing.
Mixing of theme and accompaniment with the right hand (chords).
Frequent theme harmonisation. More accurate transcription.
Movement on the whole keyboard.
Harmonised theme and multiples accompaniments performed with the right hand.
Richer orchestration.
More advanced rythmics. Several difficulties with both hands..
(numerous arpeggios, slides, triple times ...)