In Earth Defense Force 2017, gamers play with the aid of loyal AI teammates through more than 50 levels in the game as they strive to save Earth from the space invaders and their vicious attempt to eliminate humanity. Players can join forces in co-op mode and battle together, or they can go rogue and battle against friends in deathmatch. In a wholly destructible environment where bridges, skyscrapers and other structures can just as easily be destroyed by friend or foe, players can either save their world or demolish it in the process.