D-1 Grand Prix - A less spoken about feature of Digimon World 2 JP

After a bit more research, it appears this minigame that is only present in the Japanese release of Digimon World 2 is indeed called "D-1 Grand Prix" and its function more or less is just polygon battles featuring Digimon from the WonderSwan game. In the WonderSwan game you'd obtain data packs as you progress, and using some method you could import that data into this minigame to unlock more Digimon. There are more music tracks that can play during the fights, but it's random. Count on my luck to get the worst one twice. :(