"Why should I buy this version if I already have Pokémon?" you ask. Well, there's a lot of things different about this version. I'll name some. The game begins as normal, but when Prof. Oak gets you in the grass, he gets into battle with a Pikachu. He catches it.
When you meet Prof. Oak in his lab, there is only one Poké Ball on the table.
Gary snatches the ball before you.
Dr. Oak gives you the Pikachu he caught as your starter.
The ball Gary took contained Eevee.
Pikachu follows you around and can't stand being in a Poké Ball, like the TV show.
The Pikachu you take does not evolve into a Raichu.
Other Pikachus will, however.
Pikachu is always with you.
I'm guessing that Pikachu won't have terrible defense anymore.
All the pictures of the Pokémon look different.
Pikachu isn't as fat, either.
Brock, Misty, and the rest of the trainers are wearing what they wore in the TV show.
All Pokémon from Red and Blue are present, so you don't need to trade.
Pokémon are found in different areas than they are in the other version.
The Pokémon learn different moves than they did in the other versions and at different levels.
Jessie and James from the TV show replace the dudes with black clothes and whips.
Jessie and James have Meowth, Ekans, and Koffing at their disposal, and they later evolve.
You can turn around and "talk" to Pikachu any time to see his face, which reflects his happiness.
