This sonata is a titanic work of immense scope and emotional intensity, reflecting the composer's struggle and existential despair. Its dense harmonic language and demanding texture make it one of the most formidable pieces in the solo piano repertoire.
Managing the thick, multi-layered textures without losing the clarity of the melodic line is the greatest technical hurdle.
Comparable difficulty and character — good candidates for what to learn next.
Piano Sonata No. 2 in B-flat minor (Op. 36) is rated Henle level 9 of 9 — virtuoso repertoire, roughly concert / virtuoso level.
You should be comfortable at Henle level 9 — meaning you can already play level 8–9 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
A typical performance of Piano Sonata No. 2 in B-flat minor (Op. 36) lasts about 25 minutes.
Piano Sonata No. 2 in B-flat minor (Op. 36) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.
Pieces at a comparable difficulty and character include Cadenza to Liszt's Hungarian Rhapsody No.2 by Sergei Rachmaninoff, Variations on a Theme of Corelli by Sergei Rachmaninoff, Ballade No.2 by Franz Liszt — see the full similar-pieces list on this page.