Juan Alais was a prominent guitar and piano composer in 19th-century Argentina; this piece functions as an intimate nocturne. It balances a sentimental melodic line with flowing, broken-chord accompaniment.
At Henle 4 this is an intermediate piece that expects secure technique and real attention to phrasing. The main demands: sweeping arpeggio figures that must stay smooth across positions; a true singing tone, with the melody floating above the accompaniment; and a left hand with real melodic or rhythmic responsibility of its own.
Ensure the left-hand arpeggios remain supple and do not overpower the right-hand melody.
Comparable difficulty and character — good candidates for what to learn next.
A level or two down with the same spirit — ideal if this piece is still out of reach.
Where this piece's skills lead: slightly harder works making similar technical demands.
Cielo (Op.2) is rated Henle level 4 of 9 — intermediate repertoire, roughly ABRSM grades 5–6. In the RCM system it corresponds to about level 5.
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 Cielo (Op.2) lasts about 3 minutes.
Cielo (Op.2) 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 Angelita by Juan Alais, Arturo by Juan Alais, Für Elise by Ludwig van Beethoven — see the full similar-pieces list on this page.