not-bad card game
This is a card-battle game, of the type similar to Magic: the Gathering. The game system is quite sophiscated, and there is some game-playability here. But the rules get a bit overly complex, the game is a bit slow-paced, and the game interface has a lot of room for improvement. (For example, there's no simple way to check what effects are currently in play or affecting a unit. And you can't check the effect or the target of an enemy spell before playing a counter-spell, even though certain counter-spells specifically affect only the target of the enemy spell!) Also, some power cards can only be bought on-line with more (real) money, but the shop is already closed, so if you buy the game now, you will forever be at a disadvantage against on-line opponents.
In short, this is a B rate card game made into a C+ rate software. The language barrier is also very high. Not recommended unless you have near-perfect Japanese literacy, really love card games, don't mind very complex games, don't mind putting up with an inadequate game interface, have lots of time to burn on collecting cards, and have lots of money to burn on this pricey but mediocre game. (Wow, that's such a long list of qualifiers that few would meet them all, I bet.) And BTW, the game was very buggy and had some fatal bugs, so you must download the patch before you start playing.
Japan 
