What Pokemon Kanto Expansion Pak changes
How the game plays differently from Pokémon Red / Blue, then what it does to the Pokémon.
How the game plays
The Kanto Expansion Pak (KEP) is a from-scratch expansion of Pokemon Red and Blue built on the pret/pokered disassembly, not a FireRed/LeafGreen remake — the site's first Generation 1 guide. Its own README describes the goal plainly: add every "Kanto-related" Pokemon to the original games without changing the wider metagame, which the team defines as species cut from Red and Green's development, Pokemon that evolve from an existing Kanto species in a later generation, regional variants of Kanto species, or Kanto-related species from the SpaceWorld '97 Gold/Silver demo. Dark, Steel and Fairy are added as real types for the first time in a Generation 1 engine, using the SpaceWorld '97 demo's Dark/Steel matchups and Fairy's own beta chart from X and Y's development (from the October 2024 Teraleak) so the new types stay close to how Red/Blue actually plays. Kanto also gets new areas (Citrine City and its surroundings, Celadon University, Cinnabar Volcano, Faraway Island's Mew, Mt. Moon Crater, Bill's Garden) and a restructured back half: the last four gyms can be challenged in any order once Lt. Surge's badge is earned, so gym leaders scale their teams to the player's own badge count instead of a fixed story position.
The main changes
- 251 Pokemon, including dozens of prototype, cross-generation and regional-variant species new to a Generation 1 engine
- Dark, Steel and Fairy added to the Generation 1 type chart, using their SpaceWorld '97/beta-X&Y matchups
- 50 TMs and 5 HMs, the same roster as vanilla Red/Blue, with compatibility re-tuned for every new and returning species
- Wild grass, surfing and fishing tables across an expanded Kanto
- 471 trainer battles, including seven gym leaders whose teams scale with the player's own badge count
- The last four badges (Erika, Koga, Sabrina, Blaine) can be earned in any order once Lt. Surge's Thunder Badge is won
How the Pokémon change
The game leaves the official base stats, types and abilities alone. What it changes is elsewhere: movesets, encounters and trainer teams.