This made me chuckle. I'd say feel free to consider it a game. The possibility of different interpretations adds value to things (art) and we can feel free to make those interpretations. This is an idea I got from Umberto Eco's "The Open Work", which is a great book and I will definetely finish it in a decade and I'd recomend you to read it too.
Now that we (at least I) consider the jam a game, all we need to do it is submit the link for the jam to the jam once it starts and we'll have our first entry that complies to "The Decade Game" theme.
Edit after a year: https://itch.io/jam/decadejam/rate/786042