I use the word "game" as well. For the reasons Jeroen mentions. What we do is known as a (computer) game in practice. The word doesn't say anything about the content. You can still ask "what kind of game?" I'm not too fond of the term "active art" at all anymore but it was meant to answer that question, as a equivalent to the answer "literature" when somebody asks "what kind of book?"
"Game" now feels like a word on the same level as "painting" and "film" to me. Because, in my mind, it means "computer game" (probably partially because my native tongue is Dutch and "game" is a foreign word that has no meaning in Dutch apart form "computer game"). Maybe this is a form of Wagnerian claiming? We just call our work
game, even if it doesn't fit within Mr Zimmerman's strict definition, because to us "game" means
this kind of interactive stuff we do with a computer, and it does not imply any given format. Sounds healthy to me. Let Zimmerman find a new word for
his stuff instead!