Tetris 64 – a puzzle video game for the Nintendo 64. It was released only in English in Japan in 1998, and is the only Nintendo 64 game to work with the Biological Sensor accessory, included in the bundle.
The Biological Sensor is a Nintendo 64 accessory produced by SETA and was only available in Japan. It was sold alone or packaged with Tetris 64. One end of the sensor plugs into the Nintendo 64 controller’s extension port, and the other end clips into the player’s ear. The device measures the user’s heart rate and adjusts the game’s difficulty accordingly.1
The game was praised for its multiplayer mode, and at the time was the only Tetris game for the Nintendo 64 that allowed four-player mode.