Your ship is able to collect many small power-ups to build its weapon's power. Players could then unleash a large beam attack or a screen-filling energy burst that would drain their power level back to zero.
Relevant games include Border Down, the Spiritual Successor to Metal Black, later installments in the Darius series (especially G-Darius, which features a similar final boss and ending, and focuses on the beam duel mechanics), and Gaia Seed: Project Trap, which shares some themes and mechanics.
In 2016, a Metal Black DLC was added to Dariusburst Chronicle Saviors. It features the return of the Black Fly spaceship with simplified and more user-friendly gameplay mechanics, and a level set inspired by the game.
The game was rereleased on 2022 for Nintendo Switch and Play Station 4 as part of Hamster's Arcade Archives. Another rerelease by City Connection as part of their S-Tribute line is scheduled to release on February 2, 2023 for Xbox One and PC via Steam.note
The year is 2042: Earth gets invaded by aliens intending to plunder Earth for inorganic materials. Both the aliens and the area of space they came from became known as "Nemesis". Earth's troops put up a fight, but were outmatched by the alien's powerful beam weapons. However, Earth's scientists managed to obtain the aliens' weaponry for Project Metal Black, which focused on developing at least 20000 human spacecraft with the same beam weaponry. The spacecraft was known as the CF-345 Black Fly.
Ten years after the invasion, Earth unconditionally surrendered to the aliens and promised to keep all of Earth's remaining forces from attacking. This applied to Project Metal Black as well and sealed the Black Fly spacecraft from the people. The aliens ended up devastating Earth anyway via draining its natural resources, and the dying planet's capacity to sustain its population was rapidly diminishing... it was only a matter of time until someone discovered legacies of Project Metal Black and struck back.
This game provides examples of:
- After the End: The aliens have managed to conquer Earth and diminished Earth's resources. Stage 1 (a wrecked city) shows the extent of the damage done.
- Alien Invasion: And the aliens actually won and got to abuse Earth. The story takes place after they already managed to ravage most of it.
- Amazing Technicolor Battlefield: The final boss Omega Zone definitely counts.
- Attack Its Weak Point: Applies to some bosses, such as Feeder (stage 2) and Omega Zone.
- Beam-O-War: Comes in two variants. Bosses and certain enemies will fire the same weapon that you're armed with, and the shots will cancel each other. If they fire a traditional sci-fi beam at you instead, you can also spend your gauge to use yours, resulting in a clash that can also form a deadly energy sphere as a side-effect.
- Big Creepy-Crawlies: Daio & Gishiin (stage 3 bosses) fit here, as one of them is a rather ugly giant dung beetle.
- Bittersweet Ending: The bad ending. The Hero Dies, but inspires the rest of the military to resume fighting. 20000 Black Fly ships set out for battle.
- Charged Attack: Collect-type. You collect particles of "Newalone" energy to power up your beam cannons (which can be used for a radial discharge or continuous beam).
- Collision Damage: Against almost all enemies. However, averted by the Final Boss (only its core can kill you on contact, its body and tail are harmless).
- Deadly Walls: Yep, hugging a wall will kill you in this game, like most traditional shoot-em-ups.
- Eldritch Abomination: The Nemesis. They are biomechanical, space-faring monstrosities that resemble aquatic animals. The bosses explode in a mess of colors upon defeat, and the explosion patterns may look eerily familiar... Some of their creepier tactics include hiding in a shell that mimics the Moon, or teleporting using what seem to be in-universe glitches. The final boss one-ups this by seemingly straight-up warping reality.
- Flying Seafood Special: Many of the bosses and enemies are based on aquatic animals, likely inspired by the Darius series.
- Gainax Ending: The game ends after a spectacularly trippy fight against what appears to be the Nemesis leader. After defeating it, you are treated to effects on the level of a creepypasta and a view of the Earth getting sliced in two, cut to the image of the pilot of your spaceship in a fetal position, turning wireframe before another cut shows us a restored Earth, with a broken English text narration that implies the game's events were All Just a Dream... Averted if you lose at the boss fight, however; see Bittersweet Ending above.
- Giant Enemy Crab: The Mini-Boss of stage 1 is a giant hermit crab with an aircraft carrier as its shell.
- Grand Theft Prototype: Long after Nemesis attacked Earth and the world's governments unconditionally surrendered, you steal an experimental space fighter and blast your way through the remains of the local air force, then finally get to dealing with the invaders. On the other hand, after slaying the first boss, you'll have communications guiding you, and dying while fighting the final boss inspires the military to start fighting back.
- Kaizo Trap: There's one section in Stage 4 where the wall below will quickly rise and block your way, costing you a life if you haven't moved to the right preemptively.
- Mind Screw: The "good" ending. If you can make any sense out of this, you're good. (more pictures here)
- One-Man Army: Justified. The military has surrendered. You're launching the attack alone out of (presumably) personal conviction. The bad ending also shows the inspirational power of this trope, causing a true army to rise in your wake.
- Power-Up: Only one kind, which look like three coloured particles stuck together. These things power up your regular weapon and the gauge can be spent on a huge beam or a Smart Bomb.
- Segmented Serpent: Feeder, a giant biomechanical Rat-tail fish. Attack its head in order to damage it.
- Smart Bomb: Tapping and releasing your secondary attack button will allow you to shock the whole screen with arcing energy at the cost of your beam gauge.
- Soundtrack Dissonance: "Born To Be Free", the stage 1 music. It is an upbeat and hopeful tune, played over the landscape of an Earth utterly devastated by the war and by the aliens themselves.
- That's No Moon: You see a moon in stage 2, shortly after leaving Earth. You get to see the real moon shortly afterwards, then the other moon heads towards you and starts cracking...
- Translation Train Wreck: All text is in English, even in the Japanese versions of the game. The quality isn't that high, even compared to Taito's other titles of the time. This persists even in re-releases, with one renaming the Newalone particles to...neurons, which is nonsensical even for sci-fi standards.
- Wave-Motion Gun: Your Newalone energy cannon, reverse-engineered from the aliens' weaponry. It is able to destroy enemy shots too.