This sonata is a landmark of high-Classical emotional expression, noted for its stark dynamic contrasts and operatic intensity. It bridges the gap between the restraint of the 18th century and the raw drama of the Romantic era.
Executing the rapid-fire tremolos and wide-span chords with both precision and power is the main technical difficulty.
Comparable difficulty and character — good candidates for what to learn next.
Piano Sonata No. 8 'Pathétique' (Op. 13) is rated Henle level 6 of 9 — advanced repertoire, roughly ABRSM grades 7–8. In the RCM system it corresponds to about level 10.
You should be comfortable at Henle level 6 — meaning you can already play level 5–6 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. 8 'Pathétique' (Op. 13) lasts about 18 minutes.
Piano Sonata No. 8 'Pathétique' (Op. 13) 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 32 Variations in C minor by Ludwig van Beethoven, Rondo a capriccio in G major by Ludwig van Beethoven, Piano Sonata No. 17 'Tempest', No. 2 by Ludwig van Beethoven — see the full similar-pieces list on this page.