Like all Pokemon games, Pokemon Black and White have differences not only in Pokemon, but in other aesthetic features. But since this is a new region, I should probably discuss the Pokemon that can be found in each version. For Pokemon Black, you can find Cottonnee, Gothita, and Vullaby as version-exclusive Pokemon. Pokemon White features its counterparts: Petilil, Solosis, and Rufflet. Also, the legendaries and roaming legendaries of each game are different. The roaming legend in Black is Tornadus, while in White, it is Thundurus. Legendaries are exclusive to one game only, so Black gets Reshiram, and White gets Zekrom, which turns out to be a color inversion.
One major difference is the town to the right of Nimbasa City. This is either Black City or White Forest, depending on your version. Black City is a town where there are Trainers that want to battle and have some wares to sell. On the contrary, White Forest is a very lax place, where no one battles you, but tells you about the peacefulness of country life. Using Entralink between the two games, you can bring people from the other game to be in your area. Another artistic change is in Opelucid City, where each game features a different theme.
Pokemon Black’s Opelucid City is a futuristic town with doors that open automatically, while Pokemon White’s Opelucid City is an old-fashioned place with an old-style décor. In terms of battle, Pokemon Black tends to focus more on Rotation Battles, while White focuses on Triple Battles.
The Opelucid City Battle House has an Ace Trainer who will battle you every day, and his or her theme is based off your version’s preferred form of battle. A small change to the Opelucid Gym is the Gym Leader you will face. Pokemon Black players will face Drayden, while Pokemon White players will face Iris. They don’t have a change in Pokemon, though, so this difference is minor. Misaltron City’s airport surroundings are different in each version too.
Black features futuristic-looking greenhouses, while White has plots of land. I forgot to mention that the species of swarm Pokemon are different in each version. Swarm Pokemon are the wild Pokemon that are not native to Unova. A Pokemon outbreak features Swarm Pokemon, and notices can be seen in gates dividing Routes and towns. Based on the route, you can find Pokemon like Weedle in Black version, and Caterpie in White.
Each Pokemon, just like the ones in Unova, have their counterpart, so trading can quickly remedy that problem. Some players go far enough to start two games of their own if they don’t have any siblings in order to make up for the missing Pokemon in each version. Fortunately, I have siblings who do play, making it much easier for me. Version differences make games like Pokemon Black and White completely unique from each other.