Jeff Manookian’s cadenzas provide a modern, highly virtuosic perspective on the First Concerto, contrasting the original Classical charm with aggressive technical display. They are characterized by their clarity of motive and demanding fingerwork.
Rapid, clean articulation is essential to bring out the composer's intended brilliance.
Comparable difficulty and character — good candidates for what to learn next.
Cadenzas to Beethoven's Piano Concerto No.1 is rated Henle level 8 of 9 — concert repertoire, roughly diploma level. In the RCM system it corresponds to about level 10.
You should be comfortable at Henle level 8 — meaning you can already play level 7–8 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 Cadenzas to Beethoven's Piano Concerto No.1 lasts about 3 minutes.
Cadenzas to Beethoven's Piano Concerto No.1 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 Cadenzas to Mozart's Piano Concerto No.17 by Jeff Manookian, Cadenzas to Mozart's Piano Concerto No.13 by Jeff Manookian, Rhapsody in Blue (Solo Piano) by George Gershwin — see the full similar-pieces list on this page.