[[caption-width-right:332:[[CaptainObvious I think these gentlemen may wish to harm me.]]]]

--> '''''Rex''': The Earth must not be a battleground again! We defend her.''
--> '''''Rance''': And we shall never reconcile with you!''

Developed by Creator/{{NCS}} in Japan in 1990 for the UsefulNotes/SegaGenesis (and known as ''Assault Suit Leynos'' there), ''Target Earth'' is a side-scrolling shooter and perhaps one of the earliest HumongousMecha video games. It is also NintendoHard, and comes with a well-developed plot.

An OpeningScroll (briefly) establishes the background: Earth's outcasts have returned with a vengeance and attacked the planet in a vicious assault. The Earth Defense League tries its best to hold, but later levels reveal that Earth has been at least partially overrun. The end of the intro and the beginning of the game focus on Ganymede, one of Jupiter's moons.

[[TheHero Rex]] suits up in his special Assault Suit just as the base comes under attack, and so begins a brutal campaign to defend Earth from her assailants. [[OneManArmy Rex]] faces down hordes of MechaMooks, [[HeavilyArmoredMook Heavily Armored Mecha-Mooks]], [[EliteMooks Elite Mecha-Mooks]], and enemy warships, backed only by his RedshirtArmy of bronze-colored Mechs and the far more useful officers and allies who provide intel via comm transmissions. Through the course of his battles, Rex learns more about the enemy that has attacked them seemingly without provocation, and begins to doubt the righteousness of the war.

A Japan-only sequel for the UsefulNotes/SegaSaturn was released in 1997 which has a much more balanced difficulty, more Assault Suits to unlock and use, tons of customization options and a generally faster-paced gameplay. Still no less NintendoHard though. A remake of the original game by the same people who made ''Armored Hunter Gunhound'' was released for the [=PS4=] on August 30th, 2016.

!!Target Earth contains the following tropes:

* BestServedCold: The Chron survivors built up their forces for 100 years before attacking Earth.
* BittersweetEnding
* CriticalExistenceFailure: Both played straight and averted. All mooks, and the player, for that matter, can take their blows with no signs of damage and no decreased functionality. Averted with the warships, however. As you blast away their HP, they start losing parts of the ship, including turrets, making them easier to kill the closer they are to death.
* {{Cyborg}}
* TheDragon: Rance Culzus.
* EmergencyWeapon: The gatling gun that serves as your primary weapon never runs out of ammo (though it has to be reloaded every 20 shots). However, you can remove it from your arsenal during the weapon selection segment prior to each level, which would probably make most of the levels unwinnable.
* GrayingMorality: As the plot progresses, Rex begins to see that the righteous fight to protect Earth isn't as clear cut as it had seemed. In the first few levels, he's a gung-ho pilot ready to win the war. By the time he kills TheDragon, all he has to say is "Another good man dead."
* HumongousMecha: Very few soldier-level {{Mooks}} and RedShirts ''aren't'' Humongous Mechas.
* InformedEquipment: The only addition that actually appears on the player's mech is the shield--weapons all look the same and extra armor makes no changes to appearance.
* LastChanceHitPoint: The player character's health.
* KilledMidSentence: [[spoiler:Rance, as he is defiantly telling you that [[ICanStillFight he can still fight]]]].
* ManInTheMachine / CyberneticsEatYourSoul: The survivors of the OSE program became part machine in order to survive by constructing and utilizing the Chron Cyborg Creation system. What exactly that is and what it involves isn't very well explained; Rance, for instance, appears human until ''after'' his battle at one of the Chron systems, and then is sporting noticeable cybernetics--however, he says that they used the Chron to survive 100 years ago and that "now the Chron keeps us alive". It's possible that they all became cyborgs in order to survive the length of time needed to get revenge, but if they are injured in battle then they have to have even more implants added. Since the Chron isn't clarified, the reason the cyborgs are so vindictive could be part of CyberneticsEatYourSoul.
* MiniMook: Almost every enemy you face is either a HumongousMecha or some sort of oddly shaped vehicle. Towards the end of the game (or right at the beginning, depending on what difficulty you're on), dropships sometimes fly by and deploy actual footsoldiers. They're full sized humans, but to you, they may as well be ants.
* NintendoHard: With a vengeance. Your health respawns on its own, so long as you aren't constantly being damaged. Guess what? ''The enemies never stop coming.''
* NoCampaignForTheWicked: Somewhat subverted. You start off as "the good guys", but it slowly becomes apparent that there's more to this conflict than first appeared.
* OneHitPolykill: Only one weapon: the laser.
* PoorCommunicationKills: The reason for the entire war.
--> [[spoiler:Rance: We are the survivors of the Outer Space Expeditionary program. We left the Earth 100 years ago with all of man's hope. But we had trouble at the edge of the solar system. We radioed Earth for help but there was silence. We have been forsaken and are here to take our revenge!]]
--> [[spoiler:Rex: But 100 years ago there was a world war. We had to rebuild from the ground up. There was no way the Earth could have communicated with you! Your expedition held hope for us all. We never gave up that hope. Now look what a failure to communicate has caused. War.]]
* RealIsBrown
* ReentryScare: A cutscene in Stage 3 shows a friendly pilot unable to make it back to the dropship and burning up in Earth's atmosphere. This was deleted in the PAL and NTSC versions and is considered an obvious homage to ''Anime/MobileSuitGundam''.
* RegeneratingHealth: Too bad the mooks won't leave you alone long enough to take advantage of this.
* TheRival: Rance is your most persistent foe, and eventually becomes one of the few that can challenge you one-on-one.
* StoryDrivenInvulnerability: Rance's first appearance has him shoot down your friendly escort warship, and he is completely immune to damage (but doesn't attack you--apparently you're beneath his notice at the time).
* SuicidalOverconfidence: See Mini-Mooks above.
* TooDumbToLive: Literally. The enemy bombers are incapable of adjusting their altitude, leading to a great deal of laughter when they plow into the sides of mountains.
* UnflinchingWalk: [[spoiler: Rex does this in the ending.]]
* VideoGameCaringPotential: It's hard ''not'' to feel PapaWolf-y towards your allies, especially the mechs that are half your size.
** Particularly in the second mission, where you have to board a shuttle evacuating the base. As soon as you do, it closes its hatch and takes off, but the longer you stay, the more [[RedShirt redshirts]] can make it aboard.
* VideoGameRemake: Currently in the works for the [=PS4=].
* WhatASenselessWasteOfHumanLife: Rex laments Rance's death, and the entire, unnecessary war.