It's the way the mom letters are delivered through the in-game mail. The game isn't incidental to the story like in here - the very mechanics of how the game works are inherently important to the method of the delivery of the message.

We can see through the veil on this one because Zelda here could easily be anything. Could be a movie. Could be a board game. Could be a bike. But you could not replace animal crossing, and if you did, it could not work as well with the same characters (message in a MMO? Why is your Mom playing a MMO???)

Mom story had the better worldbuilding.

Anyone got a link to that?

agreed there