Antoine de Lhoyer was primarily a guitarist, and his keyboard writing often reflects idiomatic patterns common to the Classical era. This work presents a standard theme followed by six variations that showcase various decorative techniques.
The primary challenge is maintaining consistent evenness in the rapid scalar variations while keeping the melody prominent.
Comparable difficulty and character — good candidates for what to learn next.
"Introduction and 6 Variations in C major is rated Henle level 4 of 9 — intermediate repertoire, roughly ABRSM grades 5–6. In the RCM system it corresponds to about level 6.
You should be comfortable at Henle level 4 — meaning you can already play level 3–4 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 "Introduction and 6 Variations in C major lasts about 7 minutes.
"Introduction and 6 Variations in C major 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. 16 in C major by Wolfgang Amadeus Mozart, Alegretto by Franz Schubert, Alla Turca by Anton Diabelli — see the full similar-pieces list on this page.