This anime is loosely based on a comic that had a bit different background. Bidama is glass marble balls -- "Vidro" is the word for glass in Portuguese (who first brought glass to Japan), combined with "tama" - balls - with modified pronunciation. The product was a collectible marble-like toy that could be played by some customized rule. Unlike the game which was made independently, the comic and anime was made as part of marketing for this product. Originally, the music for the series was written by the person who wrote the ones for the Bomberman game. However, the producer did not like music she turned in, and about a month before it aired he called me up and told me "I'd like to replace the whole soundtrack, so I want you to create pieces as early as possible." Since the actual work for the first episode was to end two weeks ahead of its actual airing, as you can expect I could not complete it for the first episode, and the actual switch took place after the fourteenth episode.