Players take the role of Lightning Alpha, who battles against wave after wave of deadly gigantic insect and robot enemies.
Insect Armageddon predominately takes place in the city of New Detroit, the target of a concentrated bug invasion that only the EDF can stop. The graphics have been greatly improved, but still retain the arcade-shooter physics of its predecessor. Vehicle controls have been fixed, with improved
tank and
mecha vehicles that can be manned by more than one player. Credits are accumulated which are used for a wide variety of tasks. Over 300 weapons are available. These can be purchased using a new unlock system that partially replaces the in-game weapon drop system of
Earth Defense Force 2017, though some weapons are only dropped by elite enemies. Four different classes are selectable from the menu, each with special functions and exclusive equipment. All armor colors can be customized.
Trooper Armor: The standard armor with an expansive loadout. It has access to more weapons than any other class, and upgradable abilities that allow it to be a versatile, all-around unit. The Trooper Armor is also the only armor available in Survival Mode.
Jet Armor: Jet-powered armor used for flying and aerial attacks. It uses energy to replenish weapons. The jet pack allows the fastest movement across the map for any class but also the weakest protection.
Tactical Armor: Wide-ranging support armor. It is the only class that can deploy turrets, mines and radar dishes. Stronger equipment is unlocked as the story progresses.
Battle Armor: Heavy armor similar to an
exoskeleton. It is powerful but slow, comes with a portable energy shield, and can equip some of the most powerful weapons in the game. Battle armor also can release its entire pool of energy in a massive electric blast, damaging everything unfortunate enough to be close by. Both split-screen and online co-operative play are included. A six-player Survival mode is also available, with a squad of EDF soldiers defending against endless waves of bugs. ==Plot==