Flappy

Tap, click or press space to flap through the gaps. One touch too many and it's game over.

Flappy Bird was released in 2013, ignored for months, then became the most downloaded free game on both stores in early 2014 — after which its author Dong Nguyen removed it, saying it had become too addictive. It remains the most striking example of a developer withdrawing a hit at its peak.

The design is one input and one rule: tapping applies an upward impulse against constant gravity, so you are never holding a position, only choosing when to interrupt a fall. That is why it feels unfair and is not — the gaps are passable, but every correction costs altitude you have to spend again immediately.