EarthGround
This was made for the first PK Hack Jank Jam. It's a rewrite of the collision and player movement code in EarthBound to turn the game into a 2D platformer. Southwards is downwards, and you can use the Y button to jump. Complete with wall kicks, it's possible to beat the entire game in this strange way.
Additionally, the code behind it is distributed in a script you can include in your own EB hacks!