Super Sonic Saves the World

A ROM hack allegedly made by the creator of Celeste and Towerfall, Super Sonic Saves the World is described in-game as a "Collection of Short Stories" but is also a brutally difficult romhack of Super Mario World with meta-commentary surrounding the gameplay.

Notoriously difficult to acquire since it isn't hosted on any romhacking site but instead relies on "shareware" methods of distribution.