Emilio Anatra's work reflects the sentimental style of Italian salon music popular at the turn of the century. It features a soaring, emotional melodic line over a flowing accompaniment.
The primary challenge is the application of rubato to convey the intended passion without distorting the underlying pulse.
Comparable difficulty and character — good candidates for what to learn next.
'O core tanto! 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 'O core tanto! lasts about 4 minutes.
'O core tanto! 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 'A limonata by Emilio Anatra, Ballade by Amy Marcy Beach, Canto del esclavo by Nicolás Ruiz Espadero — see the full similar-pieces list on this page.