Utaco was originally an entry for A Game By Its Cover (http://www.agbic.com/).
The contest idea was to choose a fake cartridge art (with an special focus on Famicompo entries) and then develop that game in a month.
One of those entries, was うたいたガールUTACO~「IIコンは世界を救う?!」 by ふじのきともこ
The main idea of a game played with the almost never used Famicom microphone seemed fun enough for me to try to do, so that is how I choose it.
The game was not finished when the competition ended, but with some work on the following months, it reached its actual status.
The game features music by Surasshu, so go and give thanks to him later when you can’t get the tunes out of your head.