Generation II (第二世代Dai Ni-sedai) is the second instalment of the Pokémon franchise. They are sequels to the original Generation I games, Red and Green (Red and Blue for international players).
Generation II was the first Generation where Pokémon began to expand, introducing 100 new Pokémon which could not be found in the original Generation I games. Many of these Pokémon expand the evolution families of older Pokémon, while a majority of them are brand-new evolutionary families.
These games were initially called "Pocket Monsters 2". Generation II events occur three years after Generation I.
Chronologically, Gold, Silver and Crystal take place around the same time as Generation IV.
Ghost-type attacks are super effective against Psychic Pokémon. Poison attacks do normal damage to Bug Pokémon, Bug attacks now do half damage to the Poison Pokémon. Ice attacks are now ineffective against Fire Pokémon.
Some attacks have changed their type, e.g. Bite changed from Normal to Dark type. New movements are added, highlighting the Bug to balance the weaknesses of Psychic-type Pokémon.
The ability to find differently colored Pokémon, Shiny Pokémon, is added.
Possibility to visit Kanto years after Red/Blue/Yellow, with trainers with high levels, the opportunity to complete the eight Gyms in Kanto (being 16 in total in the game), and the ability to fight both Blue, rival from the previous generation and Red, the protagonist of the previous generation.
In Crystal, a female player character, Kris, can be chosen for the first time.
In Crystal, moving sprites are given to opposing Pokémon and Pokémon on their stats page.
Gold, Silver and Crystal feature infra-red connectivity to the Pokémon Pikachu and Pokémon Pikachu 2 pedometer using the mystery gift feature.