During brainstorm had this idea, that is super non-scientific, but still could be very dank: we play as a spaceship that wants to catch up with the expanding universe. Like, they learned that it is finite (limited), so let's reach the boundaries.

And you have to uprgade your ship, watch stars and galaxies flying by, upgrading your ship in an "incremental-game-like-cookie-clicker"-way, making it faster and faster, and at the end breaking some laws of the physics in a cool way, overshooting the speed of light or finding a wormhole or something: by some means reaching the universe and "breaking" its boundary in a cool final cutscene.

In the end I went for some other idea, but I would be super happy if there was anyone who made a game with such or similar base concept.