Puyo Puyo!! 20th Anniversary

It was a usual day for our protagonist, Ringo Andou. Her friend Maguro Sasaki visited Ringo and Risukuma's clubroom. Risukuma was conducting an experiment with a boiling flask, but it goes wrong, and the three were blown to another dimension...

Résumé

It is the 2nd anniversary game in the series and as such shares more similarities to "Puyo Puyo! 15th Anniversary" than "Puyo Puyo 7". This game came out 4 months before "Sonic Generations", which is also commemorating the 20th anniversary of the Sonic games.
There are 24 playable characters available, each with their own 8-stage course (similar to Puyo Puyo! 15th Anniversary).
This game, as it's predecessor, was released only in Japan.