Cinemonster's original list
There must be 31 horror films:

✅ 6 countries (other than Italy or US):
Canada: Red Rooms
New Zealand: Braindead
UK: Lifeforce, An American Werewolf in London, The Wicker Man 
USSR/Estonia: Dead Mountaineer's Hotel
Iran: A Girl Walks Home Alone at Night
Japan: One Cut of the Dead
Mexico: Huesera: the Bone Woman

✅ 9 decades: 
1920s: phantom of the opera
1930s: Wizard of Oz, Freaks
1940s: The Wolf Man
1960s: Carnival of Souls
1970s: The Wicker Man, Orca, Dead Mountaineer's Hotel, Let's Scare Jessica to Death, Torso, Ganja and Hess
1980s: Lifeforce, Night of the Comet, An American Werewolf in London, Return of the Living Dead, Day of the Dead
1990s: Braindead, Castle Freak, Hardware, People Under the Stairs, Day of the Dead
2010s: Color Out of Space, Excision, A Girl Walks Home Alone at Night, One Cut of the Dead, Swallow
2020s: Cuckoo, Immaculate, Red Rooms, Sinners, Weapons, Huesera: the Bone Woman

✅ 5 Zombie Films: Braindead, Night of the Comet, Return of the Living Dead, Day of the Dead, One Cut of the Dead
✅ 3 cult or conspiracy horror films: Cuckoo, Immaculate, The Wicker Man
✅ 1 film from a Black director with a Black lead: Sinners, Ganja and Hess
✅1 film from a Mexican or Central American director: Huesera: the Bone Woman
✅ 1 Canadian film: Red Rooms
✅ 1 Russian or former Russian state film:Dead Mountaineer's Hotel (Estonia)
✅ The most popular film from the 1940s that you haven't seen and can access:The Wolf Man
✅ 2 Post Apocalyptic horror films: Hardware, Night of the Comet, Day of the Dead
✅ 1 Film with dreams or a dream as part of the plot: An American Werewolf in London, kind of Day of the Dead , Excision, Weapons
✅ 1 The animals are pissed at us film: Orca
✅ 1 Silent film
✅ 4 based on Novels: Color out of Space, Lifeforce, Wizard of Oz, Return of the Living Dead, Carnival of Souls, The Wicker Man, Orca, Dead Mountaineer's Hotel, Pantom of the Opera
✅ Any film from THIS list that you haven't seen: Sinners, Braindead, Night of the Comet, Lifeforce, Carnival of Souls, Freaks, Day of the Dead, Ganja and Hess, American Werewolf in London, Color out of space, One Cut of the Dead, Phantom of the Opera, Return of the Living Dead, Wicker Man
✅ 1 Ernesto Gastaldi written film
✅ 1 film from 1932: Freaks
✅ I have never made a specific film a part of this before, but WIZARD of OZ ('39)

✅ And 1 Tobe Hooper Film (There must ALWAYS be a Hooper film): Lifeforce

***FOR THOSE THAT LIKE TO DO EXTRA WORK: WATCH Burn Witch Burn, German Chainsaw Massacre & Trick or Treat.