We know what you're thinking, "Why?" There's method behind the madness. EDF2P features plenty of co-op gameplay, and the limited edition double pack is available for ¥6,279 ($76). Buying two copies of the game separately would set you back ¥5,040 ($61) a piece, so it's much cheaper to buy the bundle pack.
It's kind of ingenius actually. Well it would be, if we actually cared about Earth Defence Force. /hides