Most users seek this ROM to "install" a hack. You do not install the hack on your computer; you apply a patch file ( .ups or .ips ) to the Squirrels base ROM.
: Community members often recommend checking Archive.org as a safe repository for these specific dump versions. 2. Patching Your ROM (How to Install Hacks)
Pokémon FireRed (2004) remains a popular target for ROM hacking due to its stable engine. The “US Squirrels” variant is a niche fan-made hack that replaces certain Pokémon models and in-game assets with anthropomorphic squirrel characters. The identifier 1635 likely refers to an internal build number or a CRC-32 checksum for version control.
Most modern fan games are distributed as "patches" rather than full games to stay within legal gray areas.