Online Games: Dai Guruguru Onsen (オンラインゲームズ 大ぐるぐる温泉) is a video game for the PlayStation 2 published in 2002 by Sega and developed by Overworks. It is a collection of games, featuring all games from Guru-Guru Onsen 2 and Guru-Guru Onsen 3 for the Sega Dreamcast. It features Koi-Koi, as well as the following non-karuta games: mahjong, poker, UNO, daifugō, Napoleon, reversi, and a criminal investigation video game.
The game is remarkable for having a 4-player game mode for Koi-Koi, where 2 teams of 2 players play against each other.
The Koi-Koi game features both a regular 2-player mode and a 2 vs 2 team play mode. All games support both offline play against CPU opponents and online multiplayer, though online play is probably no longer supported since the servers went down.
The gameplay is exactly the same as in Guru-Guru Onsen 2 and 3. For more detail on the Koi-Koi rules and the team play game mode, see the Guru-Guru Onsen 3 article.