In the film, demons invade the real world through a television broadcast, turning the residents of an apartment building into bloodthirsty monsters.

But the private quarters are shown behind a wall in Demons mirroring them so the only connection is the movie house was built over the Church but it never says directly.

In another apartment, a young boy left alone by his parents avoids Sally and her rampaging demon friends, but is poisoned by the bile and becomes a monster.

As they escape through a service hatch, a security guard who turned into a demon after being scratched in the face by Sally bursts through the elevator door and infects the woman.

Unable to break down the garage doors, they defend themselves against the demons with shotguns and makeshift weapons, such as Molotov cocktails.

[1] According to Bava, Argento did not interfere in his shooting, stating that "Dario, like few people, is one of those who persuades you to give your best... and I must say that at the same time he fully respected my role as the director.

[4] Both Bava and Argento purposely lowered down the violent scenes in the film in order to receive a V.M.14 rating in Italy.

[6] The third Demons film had a story developed by Franco Ferrini and Dardano Sacchetti which involved an airplane that had to make an emergency landing where it finds itself on an island with a volcano, stranding the passengers.

[7] AllMovie's review was negative, writing, "putting aside the simplistic plot, lousy dialogue and atrocious acting, Demons 2 is watchable for one reason: the bloody mechanical and makeup effects by Sergio Stivaletti".

[8] Reviewing the film on Blu-ray, Budd Wilkins of Slant Magazine rated it 3/5 stars and wrote that it "trades in its predecessor's penchant for wall-to-wall gore in favor of surreal shocks and quasi-Cronenbergian craziness".

[9] Writing in a retrospective for Dread Central, Matt Serafini called it "much more a mixed bag than its predecessor" but questioned why it never led to a series.

Serafini suggested a new generation of Italian filmmakers continue the series, including the practical effects and new wave music of Demons 2.

[10] Arrow Video released the first two films on Blu-ray and DVD on 30 April 2012 including a two-part comic titled Demons 3.