Plot: Karkurenbo Battle Monster Tactics is a Game Boy Color game released in the end of 2000. It was developed by Spiral and published by Nintendo. The game was released exclusively in Japan.
Plot: Chee-Chai Alien is a video game developed by Creatures, Inc. and released on the Game Boy Color in Japan on February 27, 2001. It utilizes the Game Boy Color's infrared port and has a built-in rumble feature. It is compatible with the Game Boy Printer. Wikipedia
Plot: R-Type DX is a Game Boy Color video game released in 1999 by Nintendo, Epoch, and Bit Studios. The game cartridge includes the games R-Type and R-Type II, as well as enhanced versions of both that includes color.
Plot: Bomberman Max is a video game released for the Game Boy Color on May 14, 2000. The game was followed by Bomberman Max 2 which was released for the Game Boy Advance on June 4, 2002. There are two versions called Bomberman Max: Blue Champion and Bomberman Max: Red Challenger. Wikipedia
Plot: Trade & Battle: Card Hero is a card battle role-playing game developed by Nintendo R&D1 and Intelligent Systems and published by Nintendo for the Game Boy Color. It was released in Japan on February 21, 2000. Wikipedia