games have followed a fairly rigid formula since the series' inception: You get a starter, collect and level Pokémon, face off against your rival, beat the region's eight gym leaders, then conquer the Elite Four.
Pokémon: Advanced Adventure, a modified version of the GBA title Pokémon: Leaf Green, follows that structure for the most part.
It's an act of mercy for which I will be forever grateful.
Ash Gray actually isn't the only ROM hack based on other pieces of Pokémon media — Pokemon Naranja (Orange), a Spanish-language hack of Pokémon Ruby, similarly follows the events of the animated series' second season, titled Adventures in Orange Island.
There's also Pokémon Adventures Red, a Fire Red hack which follows along the plot of the original Pokémon manga.