Satie's 'Allegro' is an early work that bears the composer's characteristic sparse, eccentric harmonic language. It breaks away from Romantic conventions with its dry, repetitive motifs.
The challenge lies in managing the unconventional dynamic markings and maintaining an objective, detached tone.
Comparable difficulty and character — good candidates for what to learn next.
Allegro is rated Henle level 3 of 9 — late beginner repertoire, roughly ABRSM grades 4–5. In the RCM system it corresponds to about level 5.
You should be comfortable at Henle level 3 — meaning you can already play level 2–3 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 Allegro lasts about 3 minutes.
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 Gymnopédie No. 1 by Erik Satie, Gymnopédie No. 3 by Erik Satie, Gnossienne No. 1 by Erik Satie — see the full similar-pieces list on this page.