To commemorate the 1st anniversary of Kart Rider Rush Plus, we created a celebration film with the concept of a birthday party with game users who have been with Car Ruffle. 
In this film, Car Ruffle characters play and sing Happy Birthday songs on a cake-shaped stage.
While doing so, they are using a xylophone made out of golden magnets, a piano made up of missiles, and a cloud shaped guitar, which are actually items used in the game.