Tengen Tetris is a classic puzzle video game released for the Nintendo Entertainment System (NES) in 1989 by Tengen, an unlicensed game developer. It is a version of the popular tile-matching game Tetris, which challenges players to stack falling blocks into complete lines to clear them from the screen and prevent the stack from reaching the top. Tengen Tetris has several unique features, including a two-player mode, customizable difficulty settings, and a different set of block shapes than the licensed version of Tetris released by Nintendo.