If you prefer a 2x multiplier without using external cheat engines, you can use a code to give your Pokémon a . In the standard game, this item provides a 1.5x EXP boost , which is the closest "natural" way to hit a multiplier.
If you are planning a replay of Kanto, the is highly recommended. It bridges the gap between the rigid, grind-heavy design of 2004 and the accessible, fast-paced design of modern gaming.

