Tetris

The falling-block puzzle that has never needed improving, here in a version recreating the handheld console most people first played it on. Seven shapes, one rule — complete a row and it clears — and a speed that rises until you can no longer place pieces where they need to go. What keeps it inexhaustible is that the difficulty is self-inflicted. A tidy stack gives you options; one badly placed piece creates a hole that constrains every decision after it, and a game lost at speed eight was usually lost at speed four. Good players keep the surface flat, hold one well open for the long piece, and resist the temptation to chase a four-row clear when the stack is already uneven. There is nothing else in it: no modes that matter, no progression, no reason to add any. Games last a few minutes and the score is the only record. The handheld presentation is a faithful piece of nostalgia and entirely legible. It plays with four inputs or swipes, runs on anything including very old devices, and remains the clearest example of a perfect design in the medium.