Vladislav Aloiz composed these variations in a late-Romantic language that emphasizes harmonic color and expansive phrasing. The inclusion of a formal Coda elevates the set beyond simple decorative treatment of the theme.
The technical difficulty lies in balancing the singing melody against complex inner-voice accompaniment.
Comparable difficulty and character — good candidates for what to learn next.
14 Variations et Coda sur un thème original (Op.24) 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 14 Variations et Coda sur un thème original (Op.24) lasts about 10 minutes.
14 Variations et Coda sur un thème original (Op.24) 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 Andante final from Donizetti's 'Lucia de Lammermoor' Op.44 by Sigismond Thalberg, Ballade No.2 by York Bowen, Andante final de 'Lucia di Lammermoor' by Sigismond Thalberg — see the full similar-pieces list on this page.