The "Are games art?" game.
I have written philosophy presentations on this that went on so long I had to be stopped.
A great and surprisingly simple argument for player agency. And what holds that together is it isn't just an art-bait game but a format that hasn't been matched since.
Just you, your horse, a wasteland, and a dozen boss fights.
You have no excuse to have not played it now, but is best to go in blind with zero exceptions outside of "Oh hey big monster"