It is the year 2201 and expanding technologies have given man the power to live anywhere in space. Amidst this backdrop, the story of Target Earth begins with a war between Earth against a cyborg army returning from the farthest reaches of space. In the game's early stages, the nature or purpose of these cybernetic adversaries, named Chron, is unknown. However, it is later revealed that Chron are the survivors of a failed space expedition sent by Earth a hundred years earlier. The EarthDefense League fights to defend Earth. The heart of the defensive movement is the Assault Suit—a twelve-foot-tall armored battle machine with awesome fighting capabilities. The player is Rex, an Assault Suit Wing commander and master at Assault Suit combat. The battle begins on Ganymede but shifts to battles in space, on the Earth, and inside enemy outposts.
Main characters
Rex: The hero and the game's protagonist. A master of Assault Suit combat and commander of the Assault Suit Wing on the Ganymede base. Assault Suit Wing Chief Commander: Although not officially explained in-game, this character appears to be Rex's superior and may be the chief commander of all Assault Suit Wings. Captain: A senior officer that appears in Stages 6–8 and appears to be the captain of the ship that is constructed after Stage 5. Leana: Rex's sweetheart. She supplies Rex with weapons and constantly fears for his safety. She appears on the options screen after the player utilizes a special trick to get 9 continues. Rance Culzus: Rex's recurring nemesis. A formidable opponent and commander of Chron's Attack Suit Wing. Enemy Commander: The overlord and commander of all of Chron's forces. Knows the true secret of Chron.
Gameplay
Target Earth consists of 8 stages. Much of the game's mechanics fall in line with those of horizontal shooters with some subdued platforming elements. The player's performance after completing a stage dictates what weapons, armor, and accessories are unlocked in the next stage. The game features 14 weapons, which was considered a lot of firepower for an action game in the early 1990s. The wide assortment of armaments increased replay value by encouraging the player to experiment with different ways to defeat enemies. While the official information for the game indicates that it is only single-player, it is possible for a second player to have limited control over enemy movement and attacks on screen.
Release
Certain scenes in Target Earth were censored. For example, a scene in which a comrade does not make it back to the ship in time and burns up in the planet's atmosphere was removed. The romantic relationship between Rex and Leana was also downplayed. These scenes have been restored in the remake. The Westernlocalization of the second game in the Assault Suits series, Cybernator, was also subject to censorship. The game is included on the Japanese Mega Drive Mini, with the US version being accessible if the system is set to English.
Assault Suit Leynos 2 was released exclusively for the Sega Saturn in 1997, in Japan only. The gameplay is far more challenging as the shield cannot guard infinitely.