Pocket Monsters Ao is a reworked version of Pocket Monster Akai and Pocket Monsters Midori. It was later used as the technical base for Pokémon Red Version and Pokémon Blue Version.
The gameplay mechanics stay identical, but there are some engine upgrades (graphics, sound, fixed glitches). This edition also changes the place where some Pokémon are acquired as well as which ones need to be traded from other versions.