Project Firestart Classic
The Matrix has 7 horror games on file for the Commodore 64, released between 1986–1989. 1 of them support multiplayer. They're ranked below by legacy score, so the games that shaped the genre on the C64 come first, with lesser-known picks further down.
Horror games build dread through atmosphere, limited resources and enemies you would rather avoid than fight. Survival horror in particular makes every bullet count.
Typical commitment: an evening or two (roughly 1–6 hours to see it through). Tip: Conserve ammunition and healing items, explore carefully, and play with the lights off for the full effect.