Broken and unbalanced, but still has potential.
The game has a decent story behind it. The has some similarities to the show. To simplify it up, you fight hollows. Replaying story mode is required since some missions can't be completed on the first run-through. You can skip previously completed missions.
The characters are unbalanced and broken. The difference between the characters' abilities is tremendous. Some characters are capable of taking much more damage than others and have attacks that do massive amounts of damage and cover the whole stage, while other characters can die by taking few hits, do little damage, and have a very short rage. Normally in a fighting game, the best character is the character you prefer to use. In this case, the best character is Hitsugaya. No questions asked.
The gameplay for this game is very enjoyable. Each character has a large amount of attacks with varying ranges and damages. But why stop there? Each character can chain these attacks together allowing opportunity for hundreds, even thousands, of different combos. Some characters have an unlimited number of different combos, including combos that never end until the enemy is defeated or until you choose to stop. A problem for one on one matches is 2 lines. You can jump from line to line while fighting. All this really does is encourage your opponent to spend the rest of the match running away from you, jumping from line to line, when you start winning.
For many, this is one of the highlights of the game. For me, this is one of the worst parts. Cards attain abilities such as speeding yourself up, paralyzing enemies, doing more damage, etc... Cards basically give you the ability to win battles without any skill whatsoever.
Online play. Broken broken broken broken. For a good deal of matches, the lag is unbearable and unplayable. The game makers added a neat feature... a scoreboard to show the top players in the world. This scoreboard is a cheater magnet. Disconnecting you wifi when playing gives you a connection error (obviously). Having a connection error gives you no penalty. About 75% of online players will disconnect their wifi anytime they lose, giving them incredible wifi records and riding up the scoreboard while facing no consequences to their account or file. Occasionally you will have a fun online match, but for the most part, you'll be wanting to throw your DS at a wall; however, it is addictive and you'll want to keep playing.
BDS2 is a very enjoyable game but is broken and unbalanced beyond belief. Despite the problems this game faces, I would still recommend it and consider it one of the most enjoyable fighters on the DS.
Any questions, just message me.