Bubble Shooter, from 2002, belongs to that category of games almost everyone recognises without knowing where it came from. The rules are minimal: you fire coloured spheres from the bottom of the screen into a cluster hanging above, and when three or more of the same colour touch, they pop. Any spheres left with nothing to hang from fall away and count too.

The principle descends from early-nineties arcade puzzle design, and Bubble Shooter is its most widely distributed desktop incarnation. It spread as freeware and shareware, later reappeared in countless browser versions, and eventually became a genre label in its own right rather than the name of one product. Catalogue data credits this version to the Ukrainian scene and lists it as single-player.

What makes the formula durable is the way it combines precise aiming with forward planning. A shot can be banked off the side wall to reach positions with no direct line, so a strong player is not merely matching threes but setting up the single shot that detaches an entire hanging cluster at once. At the same time the game is fully comprehensible within ten seconds and has no learning curve to speak of, which is exactly why it survived two decades of platform changes and still resurfaces in new packaging. OldGame.cz keeps a profile with screenshots and release details. The formula migrated from downloadable file to web page to phone app without changing its rules once, which is the clearest measure of how well it was designed.