I can agree with this.
Indeed anger comes from the build up inside like running 1/16s at high velocity.
At some point he uses an emphasized attack of 1 1/16s in both hands, chromatic I think, cause
it needs some puzzling.
I must admit that these are more than studies. They tell a story, perhaps even better than Chopins, I make it simple I know. But I'm serious, these pieces are neglected on the stage, luckily there are the Pierce Lanes, and Howard Shelleys, and Houghs that save them from neglect, and
utterly misunderstanding of these composers.
They are at the same time difficult, but what a result in character.
Those interested in a complete encyclopedia of piano music, there is a french one in 2 volumes, 3000 pages by Guy Sacre. This is the bible.
Pianiste magazine interviews a 24 old pianist Noark, who already recorded some cds of a russian less known composer,who tells he got the encyclopedia for his 12th birthday, and carries him everywhere around.
The books analyzes every known piano piece and tells about their composers.
I was lucky to find a copy 2nd hand, well used, but in good condition. Surely sold out everywhere, or not available.
Those who wants more details, isbn, year of pub,... just ask me.