Interesting to see that, especially the Revolutionary at 28 minutes 30 seconds - I thought only Cameron Carpenter was mad enough to attempt that on the organ (and with the feet). Then I looked around and discovered that https://music.usc.edu/sharing-the-stage/Mellan has been mentored by Cameron Carpenter.
Mellan gives an utterly breathtaking performance of Liszt's Ad nos (from memory) on Youtube as well, definitely worth a look.