The Adventure Game was an idea that I had for a while: what if the common trope of NPC's knowing they're in a game wasn't used as a horror device, but as an actual existential concept for characters in a game?
After this I decided to keep piling on tropes that I found tired and twisting them, until I had the most least generic game possible. It was a concept that was above my abilities at the time, but stretched me in all sorts of ways and made me learn things about narrative design I had never considered.
It was set up as an RPG, but had elements of different games, with different ideas floating around, a purposefully disjointed game that ran the line of being close to unplayable.