Game Freak, founded by Satoshi Tajiri, developed the original Pokémon games.
Tajiri established Game Freak in 1989 after the publication of a video-game magazine that shared the same name. The company later became a video-game developer, and Tajiri’s interest in collecting insects helped inspire the concept behind Pokémon. Game Freak worked with Nintendo and Creatures on the original Pokémon project.
Game Freak is the developer most closely associated with the main series of Pokémon role-playing games. Nintendo published the games, while Creatures participated in development and later became involved in the Pokémon Trading Card Game and other franchise projects. The Pokémon Company was formed later to manage the broader brand.
These companies are therefore not interchangeable. Game Freak is the original development studio; Nintendo is the major platform holder and publisher; Creatures is a separate partner; and The Pokémon Company manages Pokémon business operations.