Tetris

Tetris is the timeless 1989 puzzle game originally created by Soviet software engineer Alexey Pajitnov and brought to the NES by Nintendo in one of the most legally contested game releases in history. Tetrominoes — geometric shapes made of four squares — fall from the top of the screen, and your job is to rotate and position them so they form complete horizontal lines that disappear and prevent the stack from reaching the top. It sounds simple. It is anything but.

The game's genius is in its perfect difficulty curve: early levels are forgiving and meditative, but as the pieces accelerate, every decision becomes critical. The seven tetromino shapes balance each other so that skilled players can clear four lines at once — a Tetris — for maximum points, but a single misplaced piece can cascade into disaster. The catchy Type-A music, based on the Russian folk song Korobeiniki, became so associated with puzzle gaming that it remains one of the most recognized video game tracks ever written.

Tetris sold over 35 million copies across all platforms and is frequently cited as the best-selling puzzle game of all time. Researchers have studied its neurological effects — the so-called Tetris Effect where the game invades players' dreams — and it has been used in therapy for trauma and addiction. Fifty years from now, Tetris will still be played. It is the purest distillation of what makes games compelling.