From the Publisher's Website:
Grin is a free game of survival horror.
It is a rules light survival horror roleplaying system that fits on a single page. It uses a standard deck of Playing Cards as its core resolution mechanic - no dice are needed.
Fast and deadly, Grin is perfect for high mortality single session games or one shots.
The mechanics lend themselves to improvised or impromptu play with a focus on shaping memorable narratives of terror, suspense, and dread.
Will you survive?