Chaosium

used–~$15, new: $38

junior high up, should be considered PG or PG-13

low

American Lit, Science Fiction, Horror, 20th Century Lit, 1920s History

as many as desired

No. Each player is a single character.

2-4 hours (making characters is the hard part to learn)

30 minutes.

as desired

This is a role-playing game and free-form. It explores the horror mythos of H.P. Lovecraft which inspired Stephen King and other writers. References to Cthulhu are quite frequent, including Arkham Asylum in the Batman cartoon series.