Secrets - Pokemon Red, Blue and Yellow Guide - IGN

While there aren't any hidden codes in the game, there are a couple of secrets and odd glitches. Below, we list the most important ones. This page also

Pokemon Red, Blue and Yellow Guide - IGN

Pikachu - Pokemon Red, Blue and Yellow Guide - IGN

Diglett - Pokemon Red, Blue and Yellow Guide - IGN

Pokémon Red and Blue Versions - Bulbapedia, the community-driven Pokémon encyclopedia

Viridian City Gym - Pokemon Red, Blue and Yellow Guide - IGN

Celadon City - Pokemon Red, Blue and Yellow Guide - IGN

Jolteon - Pokemon Red, Blue and Yellow Guide - IGN

Unknown Dungeon - Pokemon Red, Blue and Yellow Guide - IGN

Growlithe - Pokemon Red, Blue and Yellow Guide - IGN

Flareon - Pokemon Red, Blue and Yellow Guide - IGN

Secrets - Pokemon Red, Blue and Yellow Guide - IGN

Saffron City - Pokemon Red, Blue and Yellow Guide - IGN