Flappy Bird

Flappy Bird became infamous for how much difficulty it wrings out of a single input, tap to flap upward, do nothing to fall, and that's the entire control scheme standing between the bird and a wall of pipes with barely any room to spare.

Because there's no mid-air correction beyond another tap, a steady rhythm of small taps tends to hold a consistent altitude far better than reacting to each pipe individually, players who oscillate wildly between big flaps and long falls rarely last through more than a couple of gaps. Watching the next pipe's gap rather than the bird itself helps line up the approach earlier, since by the time the bird is level with a gap it's often too late to adjust. Dinosaur Game tests a similar one-button endurance reflex with jumping instead of flapping.