Mozart's K. Anh. 10.16, '4 Spiegelkanons,' are contrapuntal studies, likely exploring canonic imitation in various forms. These pieces are valuable for developing an understanding of fugal writing and precise articulation.
The main technical challenge is maintaining clarity of each voice and executing precise imitative passages.
4 Spiegelkanons (K.Anh.10.16) is rated Henle level 6 of 9 — advanced repertoire, roughly ABRSM grades 7–8. In the RCM system it corresponds to about level 6.
You should be comfortable at Henle level 6 — meaning you can already play level 5–6 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 4 Spiegelkanons (K.Anh.10.16) lasts about 5 minutes.
4 Spiegelkanons (K.Anh.10.16) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.