Tetris 64[a] is a puzzle video game developed by Amtex and published by SETA for the Nintendo 64.

Released exclusively in Japan in 1998, it came packaged with a unique accessory, the "Bio Sensor," which alters the gameplay based on the player's heart rate.

[2] The Bio Sensor connects to the system through the Nintendo 64 controller's expansion port and analyzes the player's heart rate using a clip that fastens to the player's ear, allowing the game to adapt based on this information.

[3] Bio Tetris offers two variations that utilize this feature: Normal, which causes smaller "biotetriminos" arranged in simpler shapes to drop when the player's heart rate is low and more complex shapes to drop when their heart rate rises; and Reverse, which decreases the complexity of the shapes as the player's heart rate increases.

[5][6] Notably, Tetris 64 exclusively uses English text in its menus, despite never being released outside of Japan.