You're referring to the FireRed Squirrels ROM hack!
Most retail copies and various digital dumps are version 1.1, which changed memory addresses. Version 1.0 (Squirrels) is required because most hacking tools and "Complete FireRed Upgrade" (CFRU) engines were built specifically for the 1.0 memory offset. fire red squirrel rom
Squirrel hacks are known for being tough but fair. The gym leaders and Elite Four are no pushovers. They have better AI, diverse teams, and actual strategies. You're referring to the FireRed Squirrels ROM hack
It also includes updated moves, abilities, and items from newer generations. You’ll find Fairy-types, updated stats, and modern move pools that make every encounter feel fresh. fire red squirrel rom