Generation I

Generation I (also known as the Color Generation) was were the very first games introduced in the Pokémon franchise. The generation consisted of Pokémon Red, Pokémon Green, Pokémon Blue, Pokémon Yellow on the Game Boy and Pokémon Stadium for the Nintendo 64 in Japan, while the generation consisted of Pokémon Red, Pokémon Blue, and Pokémon Yellow on the Game Boy and Pokémon Stadium in other regions. These games featured the first 151 Pokémon in the series starting from Bulbasaur to Mew. Chronologically, these games take place during the time period of the Generation III games. These games are also all located in the Kanto region.

Gameplay
The gameplay primarily consisted of the player trying to obtain all 151 Pokémon, defeating all the Gym Leaders, the Elite Four, and the Pokémon Champion while encountering other Pokémon Trainers along the way.

To catch a Pokémon, the player, who is a Pokémon Trainer, had to walk around in tall grass to find them. When they appear, the player would get in a battle with the Pokémon where they had to lower its health by fighting the wild Pokémon with a Pokémon the player had caught. Once the Pokémon's health has been lowered, they can then capture it with a Poké Ball. However, the player can only carry six Pokémon with him. Once the player caught a seventh Pokémon, it would be transferred to a Pokémon storage system. Players can switch the six Pokémon they carry with other Pokémon they have caught by accessing the Pokémon storage system, which contains 12 "boxes" that each hold 20 Pokémon.

Each Pokémon has their own "stats", which consisted of Attack, Defense, Speed, Special, and HP. These stats increase when the Pokémon gains a "level". The lowest level a Pokémon can be is level 1, while the highest is level 100. Pokémon also have "moves", which can be used to attack another Pokémon or to heal oneself. In total, there are 165 moves in Generation I, though a Pokémon can only have four moves and will have to forget a move to learn a new one.

Pokémon also come in different elemental types. There are 15 different elemental types of Pokémon, consisting of Bug, Dragon, Electric, Fighting, Fire, Flying, Ghost, Grass, Ground, Ice, Normal, Poison, Psychic, Rock, and Water. Each element has its own weakness, such as Fire Pokémon being weak against Water Pokémon, and reversely strengths, such as Water Pokémon being strong against Fire Pokémon. Pokémon receive less damage from and deal more damage to elements they are strong against, while on the other hand dealing less damage to and taking more damage from elements they are weak against, thus encouraging the player to keep a diverse selection of Pokémon with him to counter various types of enemy Pokémon effectively.

Some Pokémon can evolve into another Pokémon. This can happen when they reach a certain level, are traded with another character or player, or are given an evolutionary stone. When a Pokémon, they are given better stats and may also change types.

The player must travel across Kanto and defeat the eight Gym Leaders at their Gyms, earning a Badge corresponding with that Gym. Each Gym specializes in a type of Pokémon, resulting in certain types of Pokémon being effective in certain gyms, while other types of Pokémon are weak in certain gyms. After defeating the eight Gym Leaders, the player progresses to the Elite Four, where he fights the four best trainers in the entire region. After defeating them, the player must then defeat the Pokémon Champion, which will result in the player becoming the new Pokémon Champion.

Players can also trade Pokémon with or fight against other players through a Game Link Cable. Some Pokémon have to be traded so that they can evolve.

Starter Pokémon
As with all other main series Pokémon games, the player can choose one of three Starter Pokémon at the beginning of the game. These first games set the stage for the tradition of Grass, Water, and Fire type Pokémon being the main three types that can be chosen at the games start. They included Bulbasaur (Grass), Squirtle (Water), and Charmander (Fire).

There was an exception to the Grass/Water/Fire type starting trio however, with the release of Pokémon Yellow, which more closely followed the anime series. Instead of any of the previous three Pokémon being available as a starter, the player instead had only Pikachu to choose as a starter, while the rival always chooses Eevee, which evolves into either Vaporeon, Jolteon or Flareon depending on the results in the battles with him at Prof. Oak's lab and at route 22.

Gym Leaders and the Elite Four
Generation I introduced a unique set of Gym Leaders and the Elite Four. All of these trainers specialized in a specific type of Pokémon and are key to progressing through the game.

Pokémon Champion
The Pokémon Champion in Generation I is Blue, the player's rival.