Actually, Kamon, I'm certain that you're mistaken. Red and Green Version were released simultaneously in Japan, as the first two pokémon games. However, Green was hardly selling at all, while Red Version was having tremendous success. (As it has been mentioned above, the main reason Green didn't make much money is because many people hate the sprites...I think they're more interesting than ugly, but that's just me)
Anyway, in an effort to rebound from the disaster that was Green Version, Nintendo decided to come out with Blue Version, which sold much better in Japan than Green.
So, when the game were to be translated and released in the US and UK markets, Nintendo made the smart decision to release Red and Blue, and no bother with Green.
I've actually played Green Version, and it is just like Blue version (except for the sprites). The gameplay is identical, and the same pokemon that were catchable in Blue are in Green.
Originally Posted by karmachameleon
i wish all of you americans would get out of my country.
Nobody expects the Spanish Inquisition.