Right where do I start. Like many people I've been a huge fan of the Pokemon games since Red ad Blue and since Ruby/Sapphire I've been doing competitive battles in tournaments and such. However after Black and White came out I stopped playing rather quickly. Some of the Pokemon looked a bit uninteresting which is something I can get over, but the game and story itself were very childish which is something I can't get over. I can't quite pinpoint why I consider Black and White to be the game that crosses the line as I generally don't mind a bit more ''kiddy'' games but something just didn't agree with me.
However lately I'm craving to get back into the games and so some serious fighting, EV/EP farming and looking for new fun combinations to use in online battles. I saw Black and White 2 were out and looking at the box as well as the dozens of spinoff games I can't quite figure out whether it's a new game or simply the Yellow/Crystal/Emerald/Platinum version of Black and White 2. I haven't been to websites like Serebii yet because the information is a little overwhelming, but also because I'm more interested in other people's opinions.
What exactly is Black and White 2? Is it exactly the same game as Black and White with some new features, or is it a completely different game?
Black and White 2 are sequels to the original Black and White with a brand new storyline.
There are several new features.
The one that excited me was the World Tournament, where you can go and challenge every Gym Leader and Champion evar (Except Koga, cuz... screw that guy apparently.)
There's a movie making minigame to go along with your dancing minigame, not my thing, but someone might enjoy it?
You start in a city that isn't even in the first B/W, and you go to the various cities in a different order, and there are bunches of new locations.
They also gave most(all?) of the legendaries brand new forms with different setups than their basic forms.
The others are right, it's the direct sequel to Black and White. I agree with drukai that the PWT is probably the best new feature. They brought back the rental pokemon tournaments again (like Pokemon Stadium on the N64).
They improved the single player a lot in my opinion by making ~100 extra pokemon available from older generations before you get to the elite four. Also there's Plat/HGSS style move tutors again with the elemental punches, random utility moves like Trick, etc.