Developer: Game Freak
Released: 1996–1999, Game Boy
Pokémon Red and Blue brought new popularity to a handheld far in its lifespan whilst introducing monster-catching RPG mechanics to a much wider audience. It resulted in massive success both in Japan and eventually in its overseas launch, paving way for Pokémania for the latter and eventually becoming one of the best-selling Game Boy games of all time.
The game appears to suffer from notorious glitches and oddities hidden within the code, from a completely different internal Pokédex order all the way up to the infamous Missingno. Pokémon. If that isn't enough, many enigmatic prerelease media and developmental leaks give hints scrapped features, and even Pokémon designs that never made it to the final!