Pokémon FireRed : Origins

The original Pokémon FireRed video game was modified to become Pokémon FireRed: Origins. The plot is not altered in any way, though the developer of the rom may choose to make some tweaks or additions as he sees fit.

Specifically, these:

Kanto is home to all 150 of the first-generation Pokemon that are available for capture.
The Sevii Islands are home to every Pokémon native to the Johto region.
– Mega Evolutions for Pokemon from the first and second generations.
– Mega Evolution is used by Rival, Giovanni, Sabrina, and the Elite 4 all together.
– A Day/Night Scheduling Method.
– The separation of physical and special abilities – The decapitalization of both.
– Amongst many others..