I encountered a bug (I guess) in the second to last form of the boss, where you have to block the stones through singing and the boy gets hurt if you block all in a sequence. I beat this form four times (due to my stupidness in fighting the last form) and one time it was way harder then the other times because there were two boys one upon the other and both were singing/releasing stones. This way I had to block six stones a sequence with always two stones coming the same time. I think I had a lot of luck to beat him/them. And when I did, one boy sunk to the side (as always) and the other stayed in his place (at this time I noticed why I had to block six notes). After that the rest was normal.
