This work by Bergunker is a high-octane display piece requiring significant dexterity. It is defined by relentless motoric rhythms that mirror the diabolical title.
At Henle 7 this is a late-advanced work — the technical demands are serious and sustained. The main demands: fast passage work that stays light and even at tempo; repeated-note passages that require controlled, springy fingerwork; and precise articulation — the difference between crisp and blurred is the piece.
Focus on even finger-independence to maintain the clarity of the rapid passagework.
Comparable difficulty and character — good candidates for what to learn next.
A level or two down with the same spirit — ideal if this piece is still out of reach.
Where this piece's skills lead: slightly harder works making similar technical demands.
Diabolical Allegro is rated Henle level 7 of 9 — late advanced repertoire, roughly ABRSM grade 8 and above. In the RCM system it corresponds to about level 9.
You should be comfortable at Henle level 7 — meaning you can already play level 6–7 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 Diabolical Allegro lasts about 5 minutes.
Diabolical Allegro 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 Piano Sonata No. 8 'Pathétique' by Ludwig van Beethoven, Étude in C minor, No. 12 by Frédéric Chopin, Prelude in G minor, No. 5 by Sergei Rachmaninoff — see the full similar-pieces list on this page.