The Pokemon hack rom of today is about Pokemon conquest and dont change too much other that optimizing the original. here is a description from Pokeharbor:
"For those that don't know, Pokémon Conquest was released in 2012, developed by Koei Tecmo, and published by Nintendo for the DS. It's a crossover between Pokémon and Koei Tecmo's Nobunaga's Ambition series, using the gameplay and characters from NA and 200 Pokémon spanning from Gen 1 up to Gen 5. It flew under the radar, only recently gaining more and more traction within the Pokémon Community. Today I'd like to present you with my take on the Ransei Region…
Story
In a distant land and in a time not too long ago, far away from the modernized world of Pokémon, lies the Ransei region. Home to 17 Kingdoms, filled with Pokémon and Warriors. Some are content with living their lives out, but most dedicate themselves to combat, using their ability to connect with a Pokémon's mind, body, and soul. Legend has it that if all 17 kingdoms are to be united under one banner, a powerful Pokémon will bestow them with a wish.
You'll be playing through the many stories of the Warlords of the Ransei Region, warriors that hold the most power over their kingdoms.
Features
R-Style Pokémon – Pokémon that have adapted their body and battle style to the Ransei Region.
Move and Ability Changes – An overhaul of Pokémon moves and abilities to better fit both the Pokémon and the game itself.
New Moves – Moves not in the base game have been added to spice up the move pool and create interesting new strategies.
Reconquered Moves – Moves made for Pokémon Conquest: Reconquered that allow for new experiences.
Modernized Stats – Pokémon have stat changes that reflect their Gen 8/7 main game counterparts.
Harder Difficulty – Teams have been curated to create a rewarding challenge, requiring strategy and quick thinking.
Minor Tweaks – Changes that help streamline gameplay such as evolution conditions or warrior skills.
Creative Base – Reconquered can be used to influence and inspire ideas that can further build the Pokémon Conquest rom hacking scene."
And remember that this game is for nds so you have to download a emulator. I use drastic simulator on my phone