The player takes control of a soldier who is part of a military group known as the Earth Defense Force (EDF) and combats a hostile extraterrestrial race known as the Ravagers. The Ravagers have invaded Earth with an arsenal of weapons including giant ants and spiders, robots, giant Godzilla type creatures and gunships.
To fight these alien forces the player can access over 150 weapons in the game, ranging from assault rifles and sniper rifles to rocket launchers, grenades and laser weapons. Some levels also contain vehicles which can be commandeered; a tank, a helicopter, a hoverbike and a bipedal mecha are available. The game takes place across 53 levels featuring destructible environments, taking place in settings such as cities and underground caves. There is no penalty for collateral damage that is inflicted on the environment by the player, for instance buildings will crumble after sustaining a single hit from a rocket launcher or grenade. Other EDF soldiers can be allied with or followed, and attack enemies on sight, as well as provide radio chatter.
There are five difficulty levels. More effective weapons are dropped by the enemies in the game at the higher difficulty levels, encouraging players to repeat the missions. In addition to weapons, armor enhancements which function as permanent maximum health bonuses are dropped along with healing items. The player also has the option to select two weapons that they can take with them before starting any mission.
Source: Wikipedia, "Earth Defense Force 2017," available under the CC-BY-SA License.