Based on Lenau's Faust, this piece depicts a wild, debauched village wedding scene with dark, diabolical intensity. It is renowned for its chromaticism and virtuosic demands that push the piano to its orchestral limits.
The technical hurdle lies in executing the rapid-fire repeated notes and treacherous leaps with absolute clarity and demonic energy.
Comparable difficulty and character — good candidates for what to learn next.
Mephisto Waltz No. 1 (S. 514) is rated Henle level 9 of 9 — virtuoso repertoire, roughly concert / virtuoso level. In the RCM system it corresponds to about level 10.
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 Mephisto Waltz No. 1 (S. 514) lasts about 11 minutes.
Mephisto Waltz No. 1 (S. 514) 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 Ballade No.2 by Franz Liszt, Piano Sonata in B minor by Franz Liszt, Après une lecture de Dante by Franz Liszt — see the full similar-pieces list on this page.