The Earth Defense Force Wiki

Simple 2000 Vol. 31: The Earth Defense Force (Monster Attack in Europe) is the first game in the Earth Defense Force series. It was released for PS2 and all subsequent games follow its concept.

Like all other games in the EDF series with the solitary exception of Insect Armageddon, it was released in Japan prior to being released elsewhere: it was released in 2003 with a PAL release in 2004.


Chikyuu Boueigun (Earth Defense Force) was part of a series of budget games produced in Japan known as the Simple 2000 series, a successor to the PS1 Simple 1500 series. It was by far the most complex game in the series, largely due to using the existing engine Sandlot had developed for the 2002 game Robot Alchemic Drive.

The game reached a moderate level of success in Japan and was then released in PAL regions; the same was true of many Simple games, which were released by Midas Interactive Entertainment, Agetec or 505 GameStreet.

While Sandlot were eager to release the game in North America, Sony were not; it is not clear what the reason for this was, though a certain event that made America less happy about images of skyscrapers exploding may have been a factor.


Monster Attack is a third-person shooter inspired by classic Western monster movies and related media and Japanese Kaiju films. The player takes on the role of a soldier in the EDF, a global military force, in the aftermath of a sudden worldwide alien assault that has already annihilated all forces outside Japan. In essence, they are playing the role of one of the soldiers who traditionally fight the alien menace in such movies while some scientists figure out a plan.

The game features 25 missions with 5 difficulties to choose from (Easy, Normal, Hard, Chaos and Inferno) and can unlock "over 100 weapons" (111, to be exact).

The game uses the same armor system found in 2017, with Armor Items found in levels providing a permanent increase to the character's maximum health if the mission is completed. The game has the fastest armor growth of any EDF game, with 4 points of health gained per armor pickup.

Japanese Box art for Monster Attack

It also has a versus mode which allows split-screen players to fight against each other, under their customised choice of terrain.

The enemies included in the game are Ants (black, red and queen), Carriers, a Mothership, UFOs, Daroga walkers and the Saurous, an enormous lizard-like monster.


The game is notably brief on the story.

Earth has been attacked after the Earth Defense Force was formed.

They attacked on May 7th 2017; in the first wave of the aliens attack nearly half of the fighting force was lost. In an effort to turn the tide of battle all remaining troops were summoned to the coalition's Tokyo headquarters.


There are three vehicles featured in this game similar to the following games in the Earth Defense Force Series:

E551 Gigantus, has a 120mm cannon and thick armor.

EF24 Bazelart, armed with machine guns.

SDL2 Hoverbike, fast bike that hovers in midair, has low health and a useable machine gun.


  • The Western name is almost certainly a reference to the infamous trading card series Mars Attacks! which featured a very similar scenario of aliens invading with giant insects, flying saucers and robots. Their motive (being jerks for the sake of it) is also the same.
  • The game was later remade as Earth Defense Force 2017.
Earth Defense Force series
Main series and remakes Monster AttackGlobal Defence Force / Earth Defense Force 2: Invaders From Planet SpaceEarth Defense Force 2017 / Earth Defense Force 2017 PortableEarth Defense Force 2025 / Earth Defense Force 4.1: The Shadow of New DespairEarth Defense Force 5Earth Defense Force 6
Spin-offs Space War AttackGlobal Defense Force TacticsEarth Defense Force: Insect ArmageddonTapWars: Earth Defense Force 4.1Earth Defense Force 4.1: Wing Diver The ShooterEarth Defense Force: Iron RainEarth Defense Force: World Brothers