hey guys,
well , yup schoenberg and bartok are really difficult,i agree,
i think thought that prokofiev could be one of the hardest, his music seems to be impossible at times, like his piano concerto no.2 , its unimaginable to think of playing that.( i heard volodos play it with such ease , but that was cause he is a master at the piano),but even his other piano concertos like piano concerto no. 3 and piano concerto no.5 are really hard, and his war sonatas, offffffffffffffffffffff too hard to think about , haha
and well gaspard de la nuit by ravel could be one of the hardest pieces, ravels and debussys other piano pieces and all too seem pretty hard, of course chopin ,rachmaninov and lizst , but every one knows they can be hard.