This is an alternate notation or edition of the same work by Eric De Lamarter. It serves as a meditative keyboard work designed to interpret the hymn's text through varied contrapuntal lines.
At Henle 4 this is an intermediate piece that expects secure technique and real attention to phrasing. The main demands: independent voices that must each sing on their own line; a left hand with real melodic or rhythmic responsibility of its own; and a true singing tone, with the melody floating above the accompaniment.
Beyond that, expect chord voicing — bringing out one note inside a handful of others, and precise articulation — the difference between crisp and blurred is the piece.
Focus on the independence of the inner voices while maintaining a consistent tempo.
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.
Chorale Prelude 'Ach blieb bei uns, Herr Jesu Christ' 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 Chorale Prelude 'Ach blieb bei uns, Herr Jesu Christ' lasts about 4 minutes.
Chorale Prelude 'Ach blieb bei uns, Herr Jesu Christ' 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 Chorale Prelude 'Ach bleib bei uns, Herr Jesu Christ' by Eric De Lamarter, Ave Maria d'Arcadelt by Franz Liszt, Chorale by George Frideric Handel — see the full similar-pieces list on this page.