Naomi Motherboard plus Sega Tetris Cartridge. The Sega NAOMI motherboard is based on the same system-architecture as the Sega Dreamcast. The NAOMI motherboard uses a Hitachi SH-4 CPU, PowerVR Series 2 GPU and a Yamaha AICA based sound system. Included is Sega's adaptation of the classic Tetris, featuring spiffed-up graphics and your typical Tetris gameplay.
Gameplay modes include single player, where you battle your way through ten stages of block-dropping gameplay. To spice things up, you select a character before each round, ranging from an angry bulldog to hyperactive monkeys. Another mode is the versus mode, where you take on a CPU challenger in a one-on-one DuelTris match. As soon as you eliminate two or more lines, they go over to your opponent's side, so the player with the quickest reflexes always comes out on top.