If you turn on the 2x multiplier at level 30 (around Koga/Sabrina), you won't break the game. You'll just save 5 hours.

Unlike a Rare Candy cheat, which grants levels without effort, the 2x multiplier retains the fundamental loop of battle-for-reward. Players still need to defeat opponents; they just need half as many victories. This preserves the sense of earned progression. The satisfaction of watching a Charmander evolve into Charmeleon after a hard-won battle against Lt. Surge’s Raichu remains intact—it simply happens after one victory instead of three. The multiplier respects the player’s time without insulting the game’s design.

Pokemon Fire Red Exp Multiplier X2 Fixed -

If you turn on the 2x multiplier at level 30 (around Koga/Sabrina), you won't break the game. You'll just save 5 hours.

Unlike a Rare Candy cheat, which grants levels without effort, the 2x multiplier retains the fundamental loop of battle-for-reward. Players still need to defeat opponents; they just need half as many victories. This preserves the sense of earned progression. The satisfaction of watching a Charmander evolve into Charmeleon after a hard-won battle against Lt. Surge’s Raichu remains intact—it simply happens after one victory instead of three. The multiplier respects the player’s time without insulting the game’s design. pokemon fire red exp multiplier x2 fixed