There are enough differences between the two to warrant playing both versions, but they're few enough that you can jump straight to White/Black 2 without missing out on anything major.
The region, Unova, is generally the same as the first games, however some of the differences are:
- New locations are accessible
- Your journey starts in a new town called Aspertia City (Hiougi Town in Japanese).
- The Unova Pokedex features 300 Pokemon from the start.
- You will be able to capture monsters from previous generations from the beginning.
- New forms of the three roaming Pokemon from Black and White:
- A new story that takes place 2 years after the events in Black & White
- All of the gyms are either modified or new
- The Pokewood movie-making minigame is a new feature to go along with Pokemon Musicals.
- Previous Gym Leaders and Champions from other regions can be battled in the World Tournament.
Keldeo obtains an alternate form by learning the move
- The storyline involves a new version of Team Plasma.
- Characters from the first game return, such as Cheren, Bianca, and N.
- Iris replaces Alder as the Unova Region Champion.
- Black Kyurem will know the move Freeze Shock, whilst White Kyurem will know the move Ice Burn.
- Black Kyurem is related to legendary monster Zekrom and White Kyurem is related to legendary monster Reshiram.