Camera shake
A brief, directed jolt of the camera that lends weight to hits, explosions and landings — pure game feel that never touches the simulation.
The trick borrows the brain's link between motion and force: a burst or a blast feels harder if the image kicks a little. The naive version adds a random offset per frame, but that looks jittery. Better is to drive the shake with Perlin noise over time and let a "trauma" value decay smoothly, an approach Squirrel Eiserloh popularised in a 2016 GDC talk.
Overdone, it turns nauseating — which is why most games ship a slider to tame or disable it. Shake belongs to the family of game feel effects: things that change no rules but make them land.