This work is built entirely around the asymmetrical 11/8 meter, creating a propulsive, rhythmic drive. The piece distinguishes itself by avoiding standard western dance pulses in favor of irregular groupings.
The primary difficulty is internalizing the additive rhythm of 11/8 to ensure the pulse remains steady without losing the intended asymmetrical grouping.
Comparable difficulty and character — good candidates for what to learn next.
11/8 (Op.24) is rated Henle level 5 of 9 — late intermediate repertoire, roughly ABRSM grades 6–7.
You should be comfortable at Henle level 5 — meaning you can already play level 4–5 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
11/8 (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 11/8 by Peter McKenzie Armstrong, 12 Variations in S-Mode, for piano solo by Peter McKenzie Armstrong, 12 Variations in S-Mode by Peter McKenzie Armstrong — see the full similar-pieces list on this page.