Strip away the squirrel logo, and you are playing the gold standard of Pokémon remakes. Pokémon FireRed is widely considered one of the best entries in the series for a reason:
The most popular fan theory ties the 1636 squirrels to Professor Oak’s unused email system in Fire Red. In the game’s debug strings, there’s a message: “Come see my new discovery — the squirrels of Route 22 are evolving!” Route 22, of course, is the competitive battleground near the Indigo Plateau, usually devoid of any special wildlife. 1636 Pokemon Fire Red Squirrels
Some believe the squirrels were meant to evolve via a now-deleted “Nut Harvest” mechanic — similar to Berry farming in Ruby/Sapphire — which would have let players grow acorns into evolution items. Had it shipped, Fire Red might have introduced Kanto’s first cross-generational evolution: Acornimbus evolving into Heli-squirrel (Electric/Flying) with the Thunderstone. Strip away the squirrel logo, and you are
Because the hacker was inserting 3D models from the Nintendo DS into a 2D GBA engine using rudimentary hex-editing and early, unstable tools (like the precursor to DS Map Studio), the game is fundamentally broken. Some believe the squirrels were meant to evolve