Metal Warriors is about the United government in the year 2102 being under siege from Dark Axis led by the leader Venkar Amon. The few remaining warriors defending Earth are known as the Metal Warriors.

After successfully completing a few missions in space (rescuing a pilot, gathering intelligence, defending a ship and capturing a mining facility) the United government disables an anti-spacecraft cannon in Alaska in order to safely begin removing Axis forces from Earth. Missions on Earth include: assaulting a facility in the jungle, fighting through bombed-out cities and capturing subterranean mining facilities. Finally, the player confronts Amon and defeats him in a battle between fully mobile flying armored suits.

One of the features that set this game apart from other mecha-themed shooters was that of multiple assault suits. The player was able to pilot six different types of assault suits, and could even use different suits in the same stage. While other shooters forced the player to remain in their vehicle at all times, this was not the case with Metal Warriors. At any time, the player could abandon their assault suit and attempt to find a new one, allowing the player to remain in the game even if their assault suit was destroyed. Instead of a health bar, the mechs all showed progressive battle damage as they took on enemy fire, like denting, loss of the suits' arms, and finally death.

All six mechs were unique in their form and function.

Nitro: The first assault suit the player is introduced to is the Nitro. The Nitro was the "basic" mech of the in-game armed forces. The primary weapon of the Nitro was a plasma rifle capable of sustained automatic fire. The melee weapon consisted of an energy-blade similar to the famed lightsaber. For defense, the Nitro was able to produce an energy shield that would protect it from incoming fire. It could also drop smaller versions of this shield that would hover in mid-air; these absorb a small amount of damage before dissipating, but damage enemies on contact. The greatest asset of the Nitro was perhaps the jet-pack, which gave it long-term flight capability. While the plasma rifle was an accurate and potent ranged weapon, the energy-blade was much more destructive in terms of raw power. The Nitro is a general purpose mech, well-suited for all types of combat. Its mobility and versatility helped make up for its lighter armor.

Havoc: The Havoc is similar to the Nitro, but appears to be an "older model" in the storyline of the game. While similar, the mechs have different weapons and equipment. The Havoc was armed with a projectile-firing, belt-fed assault rifle. Although this weapon had a faster rate of fire than the Nitro's plasma rifle, it was less powerful and far less accurate. The close-combat weapon of the Havoc was a bladed chain-weapon that had excellent range and could be swung with a fair degree of speed. Although lacking a jet-pack, the Havoc's feet were equipped with rocket-driven jumpjets, which allowed it speed across the ground or take to the air in a boost-assisted jump. Jumping in general was handled with the B button; the placement of the X and B buttons made boost-jumps a challenging prospect. Defensive measures were provided by a simple but effective ballistic shield. The Havoc was clearly designed for shock-assaults, and while not as mobile or advanced as the Nitro, the Havoc bore arguably heavier armor.

Prometheus: The Prometheus assault suit was little more than a walking gun; it is slow, yet powerful. A pair of tank-sized battle cannons sat upon the shoulders of the burly assault suit. The pilot could fire the weapon and allow the solid shell to impact with the target, or they could airburst the round, causing a multi-directional explosion of shrapnel (this was frighteningly effective in conjunction with the "rubber bullet" power-up). Close quarter combat was handled by an onboard flamethrower that was capable of covering mech-sized targets in a bath of fire, a swift death if the opponent was unable to move away. The Prometheus was also able to deploy "floater mines" which would discourage aerial targets. Because this walking tank could not jump, fly, or sprint, it was an easy target and therefore equipped with an energy shield that offered 360 degrees of protection, as well as the game's best armor (at full health, the Prometheus was capable of surviving two fully charged blasts from the Ball's fusion cannon). Although not as mobile as other suits, the Promethus carried a bridge-layer, which would allow it to cross chasms.

Spider: An advanced reconnaissance assault suit, the Spider looked much like its namesake. Bearing six mechanical legs, the Spider was able to traverse almost any terrain, including vertical walls and cliff faces. The Spider was even capable of hanging from the ceiling. The primary ranged weapon was fired by the "gun drone", a small robotic entity that hovered over the assault suit. It fired a plasma-based weapon similar to that of the Nitro. When an enemy grew close, the drone became a melee weapon by smashing into the opponent. The Spider also had a web-shooting weapon capable of paralyzing opponents. The Spider had a visually unique shield system that acted as an active-camouflage cloaking field to hide from opponents. While the cloaking portion of this ability was useless in multiplayer mode, as a result of the game's split-screen display, this shield also worked to reduce incoming damage from bullets to the Spider. Although able to jump, the Spider had no hover capability, but its wall-walking and fast rate of movement made up for this in skilled hands.

Ballistic: The Ballistic assault suit was odd in that it is both highly mobile and completely immobile. By collapsing its frame into a sphere, the Ballistic was able to speed across terrain at break-neck speeds, but in order to fire its weapons, the mech had to deploy stabilizers, effectively pinning it to the ground. The main weapon was a high-caliber machine gun. Secondary fire was supplied in the form of fusion cannon. The fusion cannon was actually more destructive than the machine gun, but needed to be charged up in order to be used. The pilot could charge for a short time and fire a burst of smaller bolts, or store the energy and unleash a massive blast that was capable of wiping out almost any target in a single shot. Armored plates served as a shield against incoming fire, and while the Ballistic mech lacked a melee weapon, it didn't necessarily need one. By rolling into a sphere, the assault suit could rotate in place to store up energy and then smash itself into the enemy. The Ball could also jump while in movement mode.

Drache: Considered to be the pinnacle of military technology, the Drache was a highly mobile aerial assault suit. Except for landing, the Drache was incapable of operating on the ground. In terms of offense, the Drache really only had two weapons. The main weapon was a rapid-fire plasma gun that was capable of firing in any direction (the direction of fire was determined by the button(s) pressed), making the Drache useful against both ground and air targets. While effective, this weapon was nothing when compared to the Drache itself. By folding inward, the Drache could dive-bomb enemy targets. While diving, the Drache was protected by an energy shield in addition to being driven by boosters. The resultant effect of the speeding Drache colliding with an enemy was devastating. Despite the lack of equipment, the Drache was extremely mobile, so the pilot was expected to make good use of that feature.

Each suit is also equipped with a backpack unit that can use backpack power-ups. These backpack power-ups were: rocket launcher, grenade launcher, mine layer, or a gravity inverter. Like the suit's ranged gun, the backpack unit may be disabled if the suit takes significant damage. Other power-ups suits can use are health power-ups (instantly restoring a damaged suit to full health), and various upgrades for the suit's primary gun.

In addition, while ejected from the suit, the player controlled a marine equipped with a pistol and jetpack. The player could fly in a manner similar to the nitro; but was understandably slower. The pistol was useless against all enemies with the exception of soldiers and scientists lacking armor. Fortunately, most enemies would ignore the player when controlling the marine. The primary purpose of ejecting from armor was either to find/switch armor, or to activate switches to open doors. Exploration was also possible because the marine could fit into smaller spaces and scout ahead without attracting the attention of most enemies.

• Armored Core
• Front Mission
• Mobile Suit Zeta Gundam
• Cybernator