From ADV:
Buyer beware - when video game obsessed Kaito Suzuki mysteriously receives a game called Gamerz Heaven, he gets a lot more than what he bargained for! Not only is he playing the game, he finds himself being sucked into it! With a boy named Nata serving as his "Navigator" in the game, Kaito will have to eliminate all of the monsters before he can enter the Second Zone. Things become difficult when Kaito realizes that losing this game had deadly implications for the real world!