It's the year GC 232 (Galaxy Century Year 232). A huge war that had begun years and years before has divided the Milky Way and all of its natural resources have been exhausted. The Milky Way Galactic Council is forced to send a fleet of starships to a nearby planet by the name of [=UP457=] in search of any resources that can replenish the ones lost during the battle.

However, during this mission, the fleet is destroyed by a race of [[MechanicalLifeforms half machine, half animal aliens]] referred to as "[[TitleDrop BIOMETAL]]" by the Galactic Council. One of the Council's super computers then calculates that the number of these "BIOMETALS" is [[ExplosiveBreeder increasing rapidly]] and will have the Milky Way completely taken over within 32 hours. So the Halbard, along with their fleet, WASP, are assigned to eliminate the hostile threat on [=UP457=].

Weapon power-ups are gained by destroying pods and picking up the released power-ups. The player also has a DeflectorShield in the form of four spinning orbs that circle around the ship when the engaged (Known as the Gel Analog Mutant, a.k.a [[FunWithAcronyms GAM]]). Charge power is drained when the GAM is active.

BIOMETAL is unique in that its soundtrack for the European and US versions was entirely created by techno group, 2 Unlimited (the selections used for BIOMETAL were remixes of songs from their 1991 album, "Get Ready!"). The Japanese version of the game featured an entirely different soundtrack which suits the dark mood better.

Not to be confused with the Biometals from ''VideoGame/MegaManZX''.
!!'''Tropes used for this game:'''

* AllYourPowersCombined: The fifth boss uses all the powers that your ship can use (sans missiles), but boosted UpToEleven.
* AntagonistTitle: The Bio Metals are the bad guys here.
* AttackItsWeakPoint: The [[SegmentedSerpent fourth boss]], and ''especially'' the FinalBoss. For the final boss, it's the chest area, not the head.
* ChainReactionDestruction: Larger enemies and bosses go down with that style with the explosions flying all over the place.
* ChargeMeter: Shows how much shield energy you have left.
* CollisionDamage: Notably averted with some enemies, such as the first boss.
* CombiningMecha: The second-to-last boss.
* DeflectorShields: Your ship can produce a ring of round objects that circle your ship. These block enemy bullets, as well as damaging enemies who touch it. ''[[NintendoHard And you're going to need them]]''.
* DegradedBoss: The second boss, a machine with [[KillItWithFire flame-throwing]] CombatTentacles, re-appeared as a MiniBoss of a later level.
* DifficultySpike: The third level, which introduces those laser-shooting enemies, and a [[DamageSpongeBoss Damage Sponge]] MiniBoss
* EvilIsVisceral: Borderline- The titular enemies may look metallic grey, but they are more like a cross between flesh and metal.
* ExcusePlot: There are evil MechanicalLifeforms running rampant, shoot them.
* ExplosiveBreeder: The computer analysis apparently shows the Biometals increasing in such a number that, if their planet is not destroyed in 32 hours, they would take over the entire galaxy!
* FoulFlower: The third boss is a many-branched alien plant with 4 flowers on moving stalks, all of which need to be destroyed. The blue flowers shoot fireballs while the red ones fire slow-moving pollen.
* FrickinLaserBeams: Your ship's laser weapon, as well as one of the weapons used by the Bio Metals.
* FunWithAcronyms: The GAM, which stands for Gel Analog Mutant. It's the name of your shield, by the way.
* HomingProjectile: One of your missile types gives you homing missiles.
* HordeOfAlienLocusts: The Bio Metals are implied to be this.
* IncrediblyDurableEnemies: And worse still, it's the DemonicSpiders who are.
* KillItWithFire: The second boss tries this to you.
* LuckilyMyShieldWillProtectMe: Somewhat averted, as certain attacks pass through it, and some shots may sneak in between the gaps.
* MeaningfulName: The Bio Metals are [[MechanicalLifeforms part mechanical, part organic]] aliens.
* MechanicalLifeforms: The [[MeaningfulName Bio Metals]].
* MirrorBoss: The second-to-last boss uses the three weapons that the player could use, except upgraded.
* MonstrosityEqualsWeakness: The first boss is one of the largest enemies in the game, and he goes down the quickest.
* MookMaker: Stage 4 has ones similar to those in the ''VideoGame/{{Gradius}}'' series.
* MultiMookMelee: Right before the final boss, you have to deal with a swarm of lots of irritatingly durable rolling enemies that homed in on the player.
* MutuallyExclusivePowerups: The three primary weapon types (Laser, Spread and Wave), as well as your missile options.
* NintendoHard: The enemies sure love to spew loads of fast moving bullets... and many of them are tough to defeat.
* OneHitPointWonder: Your ship can only take one hit to be destroyed, though your shields can mitigate most incoming fire.
* OrbitingParticleShield: The GAM, which looks like four blue orbiting balls that protect you from damage.
* OrchestraHitTechnoBattle: The US version of the game had 2 Unlimited music as the game's soundtrack. Including the boss themes. Many people did not like the SoundtrackDissonance it created, though.
* ReverseShrapnel: Your shield weapon can be shot out like this.
* SegmentedSerpent: Present as a regular enemy, as well as a boss. Obviously, [[AttackItsWeakPoint go for the head]].
* ShowsDamage: The FinalBoss. As you attack different parts of its body, you blow off its armour, revealing organic parts inside. However, you'll have to [[AttackItsWeakPoint attack the chest area]] to actually damage it.
* SpreadShot: One of the three weapons you could get. It actually did rather decent damage.
** Unless, of course, you DareToBeBadass and [[http://www.youtube.com/watch?v=2TBR2MQ87nI shotgun the enemy with it]]. Then they will go down quickly.
* ShoutOut: In the US version, the protagonists are named "Kid Ray" and "Anita", the members of techno group 2 Unlimited.
* SoundtrackDissonance: One of the main reasons why many veteran ShootEmUp players despise the US soundtrack.
* WaveMotionGun: The first boss has one, thankfully it's easy to avoid.
* [[WhenTreesAttack When Plants Attack]]: The third boss is a [[http://www.users.globalnet.co.uk/~bevhome/biometalbossplant.gif plant-like organism]] that shoots out pollen and spores.