Pokemon Black 2 and White 2 is the long anticipated game of the sequel, the the first one. This game is what happens to Unova 2 years AFTER the events that happened in the first one. all of the routes in this game have dramatically changed such as route 4, although some city still stands. These games features both forms of Kyurem, being exclusive to one another (white kyurem=white 2, black kyurem= black 2).
Unlike Pokémon Black & White, Black 2 & White 2 feature a Pokédex that contains Pokémon from various other regions of the game, with the dex having 300 Pokémon within it before the National Pokédex is obtained, making it the biggest regional Pokédex. the world of unova also has been changed, looking less like a hexagon and more like a PSP.
there are also new citys in this game. instead of the old avatar with the crazy hair everywhere, you get a person who don't have a hat and can rock his hairstyle... anyways, about the gyms, only 2 have been promoted and shown on the world-wide internet. so i suggest you not to read for spoilers.
DO NOT READ IF YOU DONT WANNA BE SPOILED!
1st gym- poison type
2nd gym- water type
just addition info about the new kyurems, they each have NEW MOVES and you catch them at lvl 50 like ordinary zekrom and reshiram (reshiram ftw!) i will update you on further info about the game
released in USA in fall 2012