Józef Nowakowski, a contemporary of Chopin, wrote this Ballade with a clear emphasis on dramatic narrative and brilliant passagework. It displays the typical Polish Romantic style through its fiery outbursts and lyrical interludes.
Developing the stamina and clarity for the rapid, percussive sections is essential for a successful performance.
Comparable difficulty and character — good candidates for what to learn next.
Ballade (Op.34) is rated Henle level 6 of 9 — advanced repertoire, roughly ABRSM grades 7–8. In the RCM system it corresponds to about level 8.
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 Ballade (Op.34) lasts about 6 minutes.
Ballade (Op.34) 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 Józef Nowakowski, Ballade No.1 by Józef Nowakowski, Piano Sonata No. 8 'Pathétique' by Ludwig van Beethoven — see the full similar-pieces list on this page.