Hi, the game's narrative goes like this:
Hank, the protagonist, is looking to demonstrate that the Earth is not a sphere. His theory is, if he digs down and the Earth is 3D, he should be able to get to the other side. If he can't, it proves that the Earth cannot be 3D (in his logic). The game is endless... That's how the game lies.
There was no way for you to find this out in game as it's not it. But that's fine, I'm much more interested in getting eyeballs on the gameplay than worrying about the theme. So we left the narrative for later.
Thanks!