Cello Fortress could have been any kind of game. The core concept is nothing more than: " a game in which a live cellist controls the game by playing cello, and plays with or against the audience ". This idea can be applied to any genre. The cello could control a brawler, a puzzler, a strategy game, a racing game, with some imagination maybe even a point and click adventure. So why did I specifically make a twin stick shooter? A lot of thinking and brainstorming went into this choice, so today I would like to explain that a bit. Doing something with improvisation on my cello and my computer is a topic I have been thinking about for years, but it wasn't until a year or two ago that it dawned on me that the cello could actually be a game controller. Before that, I was mostly thinking about writing a procedural music generator that could accompany my own cello improvisations. Quite a big step from a game, but it slowly evolved into one from there nevertheless. Knowing that ...