Parody fantasia, based on Gombert’s four-voice motet.
Aspice Domine. Ward, p.231, has charted the use of the model in the parody, which amounts to over half the total of 198 compases.
The original music and parodied music is virtually indistinguishable, but Valderrábano makes a gesture that suggests the introduction of new material in the coda 54-60 including his atypical use of Semibreve chords in 54 and 60. There are two types of parody: virtual literal quotation eg 60-119 and reworking Gombert’s material eg. 119-153. (This suggests in this work something more akin to Mudarra’s glosas).
So Valderrábano begins and ends his parody with original music with a large parody section in the middle, plus a quotation from Gombert, a repetition of 113 ff, as Coda.
The simplification of Gombert’s textures in the more literal quotes eliminates some of the voice-leading and imitations and shows Valderrábano’s preference for sonority, mood, and harmonic progression rather than imitation.
Gombert’s piece in any case, proceeds in voice pairs, not 4 voice canon, so the “feel” is not so imitative.
Valderrábano’s harmonies, particularly cadential resolutions in the opening section are arresting.

The two themes I have isolated are 1) incipit tenor; 2) recurring theme from Gombert which forms coda and developed by Valderrábano. The work is sombre, and impressive.
Given the extensive borrowing, note the unreliability of the title “en algunos pasos”!

See Ward “Parody Technique”, 216. Aspice b.8 is used from compas 29 of Va094. See Schöner (1999) 125-126 inc music ex.