Amnesia

Publisher's description:

A 16 page one-off horror scenario, containing everything needed to run a 2-3 hour horror game for 4-6 players. The characters awaken in a strange environment and must learn about their situation and themselves. Written for the Kapcon Scenario Design Contest, Kapcon 12. Includes scenario, character sheets, player handouts and maps.

From the introduction:

System: Systemless. I used a very simple d6 based system. A simple challenging action (hearing a noise, breaking a chair etc.) succeeds on a 4+ on 1d6. Character vs character actions, whoever rolls highest on a d6 succeeds. Feel free to use rock paper scissors etc., or adapt the scenario to any published system.