Unlike later games, FireRed has no roaming dogs (those are post-National Dex in FRLG via events only). That’s good. But the event-locked Pokémon (Mew, Deoxys, Lugia, Ho-Oh) are impossible without cheats or old distribution cartridges. A true 100% is technically unattainable legitimately today.
“I caught all 386, but I lost three friends, two link cables, and my sanity to the Trainer Tower.” – Anonymous 100% completer. pokemon fire red 100 save
This is the single hardest challenge. One mistake (a crit, a miss, a bad switch) resets you to 0. And you have to do it in each of the 4 modes. It’s not fun – it’s a test of patience and RNG. The final reward (a Silver/Gold shield) is cosmetic only. Unlike later games, FireRed has no roaming dogs
Without the VS Seeker, leveling 386 Pokémon would be soul-crushing. Re-battling the 6 trainers on One Island’s hot spring path (Golducks, Gravelers) is the most efficient EXP in the game. It’s slow, but reliable. A true 100% is technically unattainable legitimately today