I don't really care for Pokemon Gray. There's not really much point to it except for Gamefreak getting money because, as we know, everyone will buy the thing. Besides, Kyurem sucks ass outside of hail. I mean, it is a good Pokemon offensively, but bad speed + tons of weaknesses = you're dead. Especially with Mach Punch, Vaccum Wave and Bullet Punch around so much. Unless they give it another ability in Gray. (imagine a Speed Boost Kyurem lol, it would jump to Uber in a heartbeat)
As for this game, it looks decent, but not really something I would play. I don't really care if it leaves Japan or not.