If you are playing a Pokemon Fire Red (unmodified cartridge or official Virtual Console), you will never see squirrels or the number 1636. However, if you are playing a specific ROM hack, follow these steps reported by fans:
is not a game itself, but rather the gold-standard "clean" ROM dump of the original Pokémon FireRed Version 1.0 (USA) 1636 Pokemon Fire Red Squirrels
If a hack named Fire Red Squirrels existed with a claimed “1636” label, here’s what a review would typically cover: If you are playing a Pokemon Fire Red
: Load your clean 1636 Squirrels ROM into a tool like UniPatcher (for Android) or an online web patcher. However, "1636" is the specific requirement for those
If you are just looking to play a standard game of Pokémon, any FireRed ROM might work. However, "1636" is the specific requirement for those using patches (.ips or .ups files). Compatibility
: It is the required base for massive, high-quality overhauls like Pokémon Unbound Radical Red Pokémon Odyssey v1.0 vs v1.1
: Let's you play as a Team Rocket grunt. It features a morality system and allows you to "steal" Pokémon from trainers you defeat. Technical Review