Developed by Vicious Cycle Software, and published by D3 Publisher ,Earth Defense Force: Insect Armageddon is a third-person shooter and is the sequel to Earth Defense Force 2017.The player defends a fictional city called New Detroit against an alien invasion, aided by bio-engineered terrestrial insects. The Player goes by the name of 'Lightning Alpha', leader of an elite team of fighters, known as "Strike Force Lightning." Along with two squad mates, Lightning is (usually) aided by local EDF fighting forces in the area, though they are little more than cannon fodder compared to Lightning.The story is separated into 3 chapters, which are divided into separate missions. The first chapter is akin to an introduction to the game, while the second chapter has Strike Force Lightning moving across industrial New Detroit to discover the fates of several downed Landers scattered across the city, as well as their pilots. All but one are salvageable, and it becomes piloted by a Captain Sully, a character that returns in later missions. The third chapter follows the story of Lightning finding and transporting "The Cube" to a nest in central New Detroit. Before it is deployed, an Ant Queen emerges from the nest, forcing Lightning to do battle with it to secure the drop zone.
Over 300 weapons are available. These can be purchased using a new unlock system that partially replaces the in-game weapon drop system of EDF: 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: Trooper armor is the standard loadout for EDF soldiers. 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 armor is a suit Lightning Alpha can acquire to take the fight to the skies. 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: Tactical armor fulfills a wide ranging support role, and is the only class that can deploy turrets, mines and radar dishes. Stronger equipment is unlocked as the story progresses.
Battle Armor: Battle armor transforms players into a veritable walking tank. Slow moving and hard-hitting, it comes equipped 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.