It would be a great idea to put difficulty settings on all the sheet music, the reason I say this is because there are people of all skill levels and will see pieces that they want to play but then realise that the piece of music is too advanced for them ~ it would be easier to just be able to scroll through the music with just a note of the difficulty beside each piece ~ (perhaps a typical colour system : green(easy) yellow (advanced) red (very advanced) etc. please do this!