A Spanish ROM hacker by the name of Ruki is responsible for the creation of Pokemon GS Chronicles, also known as the Pokemon Fire Red Hack. Ruki and a few of his buddies have been working on this project for a number of years. Their history and their conclusions will not, under any circumstances, dissatisfy you. This game is based on the original version of Pokemon Fire Red, but it presents players with an entirely new storyline as well as additional elements that have never been seen before.
FEATURES
– A new storyline keeping the essence of the original games
– New unseen characters
– A fully new scripts in all maps
– Johto region maps in a full HGSS style.
– The introduction of the Mega Evolutions in the main storyline
– RSE Tileset system
– A Day & Night system with clock-based events
– Wild Pokemon switching depending the time
– Original soundtracks of HGSS (Using GoGoJJtech’s patch as a base, messed songs ported from HGSS by me)
– Physical/special movement division.
– Some new Pokémon from 4th to 6th generation.
– New mechanics to replace the MO
– New movements from 4-7th generation, some invented by me.
– Updated type table.
– New puzzles and mini-games included.
– Many renewed graphics (such as battle backgrounds, backpack, Trainer card, etc.)
– Most trainers with different Pokémon in their teams.
– Some new locations in Johto and Kanto
– Screams of the Pokémon updated to 7a. generation.
– New locations of some Pokémon.
– Messages from coaches in battle.
– Functional PokéGear.
– Exp. Share and experience gain closest to Sword / Shield mode (but de-activatable)
– Mechanics, objects and more updated to the 8th generation.
– And more …
More information
https://www.pokecommunity.com/showthread.php?t=340232