About Global Defense Network, The GDN is a combination of fast-paced shooter and rhythm action game with a sci-fi plot throughout.The Global Defense Network has released their proprietary training simulator to the public. Chargedwith defending against aggressive extra terrestrial activity, the GDN has begun to seek out giftedindividuals to assist in their efforts. Get the game, test your skills, and see if you are good enough to be a GDN Agent.