If you prefer to download mp3 files for later terror - which is the Infocult way - the Internet Archive has a nice set.
The Nightfall Project offers this tantalizing sketch:
[W]at made NIGHTFALL such a popular series at the time, and what makes it so popular among radio drama enthusiasts today, was Howell's vision of a show that pushed boundaries. Some episodes were so terrifying that the CBC registered hundreds of complaints and some affiliate stations — ones that carried certain CBC programs to outlying areas in the Provinces, but were not CBC stations in themselves — were forced to drop the series. Episodes like the previously-mentioned Repossession (which featured the sounds of a man tearing out his own heart), The Blood Countess (which aurally portrayed some of the hideous acts carried out by the Countess Elizabeth Bathory during her reign in the 17th Century) and The Porch Light (a tense psychological thiller about a couple trapped in a secluded house and haunted by the spectre of a pajama-clad man standing under their porch light in the midst of a raging blizzard) contributed to the collective nightmares of the listening Canadian public.