Monothematic fantasia (with one short sub-theme).
Mode indication relates firstly to the theme, as well as melodic range of S., but tonality is A min. Treatment of theme is almost entirely imitative, and there are some good examples of competent 3 part and 4 part canon, which suffer from being over-written and consequently too dense. (bars 28-34; 40-42). They also suffer from lack of harmonic direction.
Cadential sub-theme 2 enters in bar 20 towards K at 23 (exactly mid-point!) followed by paring down of texture. Printing errors, and usual weaknesses spoil the work. Theme usually appears in transposed from starting on A. Perhaps whole work is transposed Dorian.