Telemann's TWV 1:18 is a compelling Baroque cantata movement, often transcribed for keyboard, which features a sophisticated fugal exposition. It expresses profound lament through its intricate contrapuntal lines and expressive melodic development.
Demands excellent hand independence and control over voice leading.
Ach Gott, wie manches Herzeleid, TWV 1:18 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 Ach Gott, wie manches Herzeleid, TWV 1:18 lasts about 5 minutes.
Ach Gott, wie manches Herzeleid, TWV 1:18 is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.