From the introduction: Trigger Warning is a game for 2 players. One player plays a sniper watching their target while waiting to pull the trigger. The other player plays the target. To play you just need a pair of two way communication devices (Walkie Talkies, A Cell Phone, or a wireless phone work), some kind of optical magnification (Binoculars, A monocular, a rangefinder, a rifle scope, or a camera with good zoom) and a good location.