Seismic shifts

QUAKE (a UZZ sequencer): it moves one step per bar, clocked from the end of each kick-sequencer cycle. The 16 bars go F ×4 → Db ×2 → Eb ×2 → Bb ×4 → C ×2 → Gb (shock bar) → C.
Key changes: two more UZZs move your 303 acid line and the lead (from the UNIT-D sequencer) into each new key, so the whole band shifts together.
Each key change: a sub on F1 drops about 2 octaves over roughly 4 seconds, with a resonant red-noise rumble tuned to the current key. The kick pumps both.
Aftershocks: the Bb change hits twice and the Gb shock hits three times.
Tension: QUAKE also lengthens the acid decay and opens the second 303’s filter envelope as the form builds. Both peak on the Gb bar.

Acid tones

SQUELCH: a new 16th-note counter-line in F harmonic minor (F3 F4 Ab3 – C4 Db4 C4 E3 …) on a second 303 using the square wave. It has heavy resonance, slides and accents, a few notes that sometimes skip, and a double hit near the end of the bar.
Slow drift: an LFO with a 32-second cycle moves that 303’s cutoff and your delay’s feedback.