I've not quite heard a 303 used like this before. Imagine tweaking those knobs to the max and back again, putting the result through some mad filters, applying several layers over a throbbing 303 originated bassline and you might get somewhere near to the sound that Walker has created. My copy is a poor pressing on red vinyl (see pics) which is part of the reason I never had the balls to play it in a club, but the main reason is fear of killing some unsuspecting punter. Death by 303 what a way to go.