In a World… populated by sentient robots, a mysterious vessel known as the Ark is discovered during a digging operation. A group of violent robots known as the Virus Army emerged shortly thereafter, attacking the Mega City with the goal of world domination. While the civilians could not fight them off, nine Guardians of the Guardian Corps wielding the power of Circuits appeared to fend off the invaders, though in the aftermath only one Guardian remained: the Gravity Circuit who was heavily damaged and was kept in stasis to recover.
Years later, the Virus Army has re-emerged and begun to attack the city once more. While the Guardian Corps are fighting a losing battle, the Gravity Circuit Kai miraculously recovers from his injuries to combat the returning threat. The other eight Guardians have also returned, though now they are working for the Virus Army, so Kai must fight his old allies to save the world with Kernel of the Guardian Corps and the eccentric Nega helping him out.
The gameplay is reminiscent of the Mega Man series, though more focused on melee combat than Run-and-Gun action. Players control Kai as he fights enemies using various attacks that are executed differently depending on directional input. Once enemies take enough damage, they enter a stunned state where they can be grabbed before they explode using the hookshot (which can also be used to latch onto surfaces to pull yourself or swing towards your desired destination) and thrown at other enemies. At the end of each stage, there is a boss fight against the stage's Rebel Circuit, and defeating them allows players to purchase and equip their moves to be used as Burst Techniques if they have any Burst Charges in stock. Stages also contain civilians to be saved, which can be traded for Booster Chips that give passive abilities such as a damage reduction or a double jump.
Gravity Circuit contains examples of:
- Achievement System: The Challenges, which are concurrent to the game's Steam Achievements. Examples of these include "Clear a stage/Beat a boss without taking damage", "Beat a boss using a Burst Technique" and "Clear a stage without taking damage from hazards".
- A.I. Is a Crapshoot: A benevolent example - after seeing that they were, effectively, leaving the sentient worker bots to die and rust away every time the Ark left for another world, the Circuits sans Commander broke from their mission and vowed to protect the bots on their current planet. The Commander Circuit serves as the game's villain primarily due to his continued devotion to the Masters' mission.
- Air-Dashing: Gravity Dash functions as this, allowing the player to fly in the direction inputted.
- Alas, Poor Villain: The Commander Circuit's last words have him lamenting never seeing the stars again, putting into perspective just how much his existence has been a prison for him.
- Aliens Never Invented the Wheel: This all-robot civilization must have stored all their data digitally, as physical books had only just been invented at the start of the game.
- Amnesiac Hero: Kai's is unable to remember anything that happened from the last Virus Army attack, implied to be caused by his injuries. As revealed later, he doesn't remember because he's not the same Gravity Circuit.
- Anti-Frustration Features:
- If the player falls into either spikes or a bottomless pit, or gets crushed, rather than instantly dying like in many traditional platformers, they instead take 5 points of damage (which can be lessened to 2 with a Booster Chip) and respawn at the last safe place they came from.
- Holding the grapple button while defeating an enemy with normal punches/kicks will grab them if the attack dealt a KO.
- The player can refill their health and Burst Charges at checkpoints for a small fee so they don't start the upcoming boss fight at a disadvantage.
- Rather than a single achievement for finishing a
Minimalist Run, the game has four: one for each type of upgrade the player can obtain. This way, the player can attempt the achievements across multiple playthroughs if it's too challenging without the upgrades. But they can still choose to do all four at once as a Self-Imposed Challenge. - The Circuits fought during the obligatory Boss Rush have one health bar as opposed to the two they had for their own dedicated fights. Additionally, the player doesn't have to go through all of the Circuits in a single run. The defeated Circuits remain defeated if the player dies partway through.
- Background Boss: The Final Boss is this, in a similar vein to Sigma from Mega Man X.
- Band Land: The City Center has been taken over by Medley, the Wave Circuit, and part of her dangerous installations includes placing massive speakers all over the place that damage Gravity Circuit if he's too close when they go off.
- Batman Gambit: The Commander Circuit hijacks Kernel into taking the Rebel Circuits to the Ark so that Kai, the Gravity Circuit, follows him there, allowing the ship to take off into space.
- Beware the Silly Ones: Kernel on the surface seems like a Pointy-Haired Boss whose Skewed Priorities during mission briefings are the game's Running Gag. However, it's noted in lore that he earned his position because of his evacuation efforts in the first Virus Army encounter and is a genuinely skilled combatant. Unfortunately, he only gets to show this off after falling under the control of the Commander Circuit.
- Big Bad: The Commander Circuit, the source of the Virus Army and the tenth Circuit.
- Big Boo's Haunt: The Junkyard, which contains many undead robots rising from piles of junk.
- Bittersweet Ending: Kai puts a stop to Commander Circuit and his Virus Army, ending their threat for good... but Kai was forced to kill Kernel thanks to Commander's control of the latter, and Nega became the next Commander Circuit to ensure that the bots on the planet will still be able to function.
- Blow You Away: Blade's Burst Technique has him surrounding himself in a hurricane that pulls the player in. And he also sweeps across the stage for Collision Damage.
- Boss Corridor: As to be expected from a game that takes many cues from the Mega Man series.
- Boss Rush: At the end of the second Ark stage, though with a small twist: during the fight with the Circuit Crystal, Kai will be transported to one of the Rebel Circuit's arenas to fight them, rather than having a dedicated room with teleports or having them fought in a set order throughout the stage.
- Brainwashed and Crazy: Kernel is hacked into by the Commander after defeating all eight Rebel Circuits.
- Catch and Return: Kai can use his grapple to do this with some enemies' projectiles. If you rematch Nega while wearing the Stained Purple palette and try to throw a block at him, Nega can catch the block and throw it right back at you. After all, it was his move first.
- Climax Boss: Nega, whose boss fight comes directly after The Reveal that he is in fact the original host for the Gravity Circuit. The fight is a Mirror Boss that serves to test both Kai and the player’s skills. In addition, Nega is the only boss other than the Final Boss to have three health bars.
- Counter-Attack: The Catch Interrupt technique allows Kai to counter any physical attacks that come his way.
- The Cracker: Hash, the Cipher Circuit, attempts to hack into the city's computer systems from a warehouse and hides himself in cyberspace.
- Cyberspace: Warehouse Area has you transporting to cyberspace near the beginning of the stage.
- Dance Battler: Medley, the Wave Circuit, uses pirouettes and sound waves as her main forms of attack, and the fight is framed as a performance. If Kai finds the palette chip on her stage, he can do the same pirouettes as she can when jumping.
- Dark Is Not Evil: Nega has the design of a villainous robot, being dark purple in color and having a very angular visor, but he's firmly against the Virus Army. His boss fight against Kai is just to ensure that Kai is strong enough to take on the Commander.
- Deflector Shields: Hardware Barrier creates a barrier around Kai that absorbs an attack to create a damaging shockwave. Commander Circuit uses a similar technique, Burst Shield, to protect Kernel during his fight.
- Desperation Attack: The Rebel Circuits, Nega, the Circuit Crystal, and Kernel (via Commander Circuit) use their signature Burst Technique upon losing the first portion of their health, and will use it occasionally during the fight itself.
- Eternal Engine: The Steelworks. All three Ark stages also embrace the aesthetic, the second one especially.
- Evil Cannot Comprehend Good: The Commander Circuit fails to understand why the Circuits defected and assumes they started protecting the native bots in order to be worshipped by them. He then angrily remarks that he could've just made them new bots to do that. Nega reveals afterwards that the actual reason was that every time the Circuits left the planet, all bots on it would effectively die, and the Circuits defected when they found out.
- Eurobeat: Some of the game's soundtrack dips into the Eurobeat style, particularly the game's Circuit boss theme (Deletion Duel) and the Highway stage theme (Theme of Bit).
- Fastball Special: Whenever enemies are stunned, they are able to be picked up and thrown at other enemies, dealing enough damage to instantly stun weaker enemies.
- Flunky Boss: Trace summons enemies during the second phase of her boss fight, who you can then stun, grab and throw at her to send her flying across the room without the need of a Burst Technique. The Commander Circuit also does this during his final phase, and the best way to damage him there is to throw stunned enemies at him.
- Flying Face: The Commander Circuit is just a head with floating hands.
- Foreshadowing: There are a few hints to Kai and Nega's connection throughout the game.
- From what little you can see of Nega under his cloak, he and Kai have similar forearms.
- Nega has in-depth, undeniably personal knowledge about all the Circuits, which he shares with the amnesiac Kai after each is defeated.
- Kernel informs you that the Guardian Corps borrowed the shape of the Gravity Circuit for their insignia. However, the banner at HQ that displays it is purple rather than Kai's red. Underneath the cloak, Nega is the same purple shade. Perhaps not by coincidence, he can usually be found in the same room.
- As of update 1.0.8, a training room is tucked away above the teleporter at HQ, with a room between the two. This room features a shattered window, with the drapes also being largely torn off. It's another sign of Kai's escape from HQ alongside the damaged healing tube...or so it seems, until you realize the drapes look awfully like Nega's cloak. It's the only thing that specifically foreshadows that he, and not Kai, was the one to bust out of HQ, with his disguise coming from said drapes.
- We're shown (and told, by Nurse) that the Kai broke out of the healing tube and escaped Guardian HQ to fight off Virus Army. But the the intro stage opens with Kai, atop a train, approaching HQ from outside. Much later, Kai is revealed to have been wandering the forest outside the city without a mind or purpose after gaining the Gravity Circuit, only regaining his senses once Virus Army re-emerged.
- Gentle Giant: Crash, the Break Circuit, is relatively calm in addressing Kai in his pre-fight dialogue compared to the other Rebel Circuits, lamenting that the two are on opposing sides.
- Goomba Springboard: Using your down-angled mid-air attack, you can bounce off of enemies. The Mountains in particular has you doing this across bottomless pits.
- Greater-Scope Villain: The Masters, who are the superiors of the Circuits and the driving force behind the Commander Circuit's actions.
- Ground Wave: Whenever Medley lands on the ground during her boss fight, she releases a wave of energy across the ground. Kai replicates this with the Surface Render Burst Technique.
- Heart Container: You can find a pick-up in each of the eight Circuit stages that either increases your max health or your energy capacity for finishing moves.
- Heroic Sacrifice: At the end of the game, Nega opts to take the Commander Circuit for his own to ensure the Ark stays active and robotkind can continue to live on the planet. He seems self-aware about the sacrificial element.
- An Ice Person: Blade, the Cooler Circuit, combines ice attacks with harsh winds, and is holed up in the ice-themed Mountains.
- I Shall Taunt You: Hash will point and laugh at you if one of his clones manages to shoot you, or at random. Hitting the real deal while he's laughing nets you an achievement.
- Justified Extra Lives: Kai respawning after destruction is the purpose of the Gravity Circuit - when its host is destroyed, the Circuit attempts to reassemble them, or take on a new host if it can't for whatever reason.
- Kamehame Hadoken: Ray's Burning Laser fires a huge beam of energy that pushes him backwards due to recoil. Kai can replicate this using the Erupting Beam.
- Lava Pit: There is a lot of deadly lava in the Steelworks.
- Legacy Character: The nature of the Gravity Circuit, should its current wielder be unable to be revived for whatever reason - it will seek out the nearest bot and turn them into the next Gravity Circuit. Nega was its former wielder, with Kai being the latest bot the Circuit has been wielded by. At the end of the game, Nega becomes the Legacy Character for Commander Circuit by taking his Circuit to become the new caretaker of the Ark.
- Limit Break: All Circuits have Burst Techniques. Kai can perform up to four equipped techniques if he has any full Burst Charges, and they generally deal huge amounts of damage.
- Locomotive Level: The Highway.
- Multiple Life Bars: All bosses (aside from the Rebel Circuit rematches during the Circuit Crystal boss fight) have two life bars. Nega and the Final Boss have three life bars. Kai can also pick up health upgrades that add four pips each to a second health bar.
- Megaton Punch: Flying Strike is a dash punch that launches enemies away when it connects.
- Mercy Invincibility: Kai has the standard implementation of this mechanic, but bosses work differently - they can take damage freely up to a point (about 4 damage in rapid succession), in which case they'll be put into an invulnerable state for a few seconds.
- Metropolis Level: Central Station, the first level of the game.
- Mirror Boss: The boss at the end of the first Ark stage. Nega, as the original Gravity Circuit, posesses the same brawling capabilities as Kai, and throughout the fight will unleash similar moves to his own. To a lesser extent, every boss is this to a certain degree: their Desperation Attack will create similar move name text at the top of the screen to Kai's own Burst moves.
- Mission Control: Kernel of the Guardian Corps. He is replaced by Pat once the final stages are made available.
- Monster Compendium: There are Data Chips containing information on the enemies and bosses fought in the game which are dropped whenever they are defeated, as well as chips for NPCs dropped by interacting with them. These can be researched by Alph.
- Mr. Exposition: Nega, who gives backstory on the Rebel Circuits and their purpose each time you talk to him after defeating one. He also explains the nature of the Gravity Circuit, the Ark, and Kai's origins when playing the Ark stages.
- Ninja: Kai. His design heavily resembles one, along with the flipping, afterimage dash, wall jumping ability, his professional manner of speaking, and the glowing light trail that follows him as he runs, which vaguely resembles the stereotypical ninja scarf.
- Non-Indicative Name: The Gravity Circuit doesn't seem to have any powers related to gravity. Lategame exposition provides an explanation: the "gravity" refers to what the circuit does after its host expires, using it to find another host or create a new one.
- No Ontological Inertia: It's revealed that if the Ark leaves the planet the game takes place on, all the inhabitants will shut down and cease functioning.
- Not Quite Dead:
- The Circuits' cores are contained in the crests on their foreheads, including their memories and personalities, and can be reconstituted from them as long as the Circuit remains intact.
- Nega suffered this at the end of the first Virus Army attack, succumbing to power failure rather than being outright destroyed. Because the "Copy" command couldn't be sent, the Gravity Circuit thought he was completely dead and separated from him to find a new host. Nega's body was recovered by Guardian Corps afterward and eventually repaired.
- Player Headquarters: Guardian Corps HQ. Initially it only contains a few NPCs, but more of them start to appear there as you save civilians in the stages.
- Playing with Fire: Ray, the Optic Circuit, uses burning-hot lasers and a flamethrower as his primary weapons.
- Poor Communication Kills: As Nega admits, the Guardians could have prevented the Virus Army from ever being formed if they had just told the Commander Circuit that the bots created by the Ark were sentient rather than bury him underground for centuries out of fear of him rejecting their rationale for staying.
- Power Copying: Kai obtains two moves from defeated Rebel Circuits to use as Burst Techniques, which are available to purchase from Nega or Nurse once the final stages are unlocked.
- Projected Man: Hologram Trap creates a holographic clone that explodes after a few moments or upon contact.
- Punny Name: Each of the Circuits has a secondary name that also refers to their element. The music-slinging Wave Circuit, for example, is named "Medley". Some of the NPC bots also have puns in their names, such as Guardian Corps leader Kernel.
- Red Herring: Nega comes off as suspiciously knowledgeable for a "humble traveler", being able to recount many details of the Rebel Circuits and even being able to sell you Burst Techniques based on each one you defeat. Additionally, his shade of purple is extremely similar to that of the Virus Army. However, he turns out to be one of the most objectively good characters in the game, his knowledge coming from the fact that he was the previous Gravity Circuit, who hasn't lost any of his integrity.
- The Reveal: Nega is the original Gravity Circuit from the first Virus Army conflict, whose circuit detached from him after he ceased functioning and attached itself to a new host, an ordinary robot who would later be known as Kai. The nine Guardians are also servants of their Masters, whom they defected from after realizing they were leaving innocent robots to die each time they left a planet.
- Rewatch Bonus: When Nega reveals himself as the previous Gravity Circuit, his pauldron on his right shoulder is missing. During the intro cutscene, the wounded Gravity Circuit that Guardian Corps recovered after the first Virus Army attack is missing the same pauldron.
- Robot Dog: Amadeus and Yuki.
- Running Gag: During Kernel's exposition for the goal of each mission, he'll make a deflating comment at the end which seems very low-priority for what's happening at the moment (like asking Kai to bring back some snow so he can cool off his servos, or wanting Wave Circuit's e-signature), much to Kai's mild annoyance. He'll make a related comment in the debriefing after every mission too.
- Shock and Awe: Cable the Power Circuit has electric powers, which in turn powers the electric floors on the ground of his boss arena.
- Shoryuken: Rising Upper is one of your first moves and works as such. It even gives you lift if you use it mid-air.
- Shout-Out:
- Many to the Mega Man series. Not surprising due to the game sharing more than a few elements of the series.
- The Circuits are stand-ins for the Robot Masters or Mavericks of the series, being a group of eight, each with their own theme or element, and which pose a danger to society.
- Kai's grapple looks and functions similar to Zero 3's Chain Rod, including the ability to swing from platforms and ceilings.
- Shift Circuit's Burst is named "Screen Divider", after Colonel.EXE's signature move.
- One major example is the mech you control in the Ore Mines, which is basically the Ride Armor from Mega Man X.
- The Highway stage, as is customary in Mega Man stages with similar titles, features a pair of giant helicopter Mini Bosses.
- Bit makes his entrance by outracing the train on foot and jumping aboard, much like Slash Beast.
- The stage being a transport convoy Kai crosses over while dodging oncoming road signs brings to mind Panter Flauclaws' stage from Mega Man Zero 2.
- The Reveal that Kai isn't the original (or even the second) Gravity Circuit mirrors a similar reveal at the climax of Mega Man Zero 3.
- The game's Final Boss is set up similar to the Sigma fight from Mega Man X: a fight against a mobile character favoring close-range melee, followed by a Background Boss with big floating hands.
- After beating the Final Boss, Kai stands on a cliff overlooking The Ark as he contemplates his journey, which is framed in the same way as X doing likewise outside Sigma's fortress in Mega Man X.
- Kai's grounded up attack looks similar to Rugal's Genocide Cutter.
- Before his boss fight, Bit tells Kai to "show [him] your moves."
- Many to the Mega Man series. Not surprising due to the game sharing more than a few elements of the series.
- Sigil Spam: Everything related to the Guardian Corps has the Gravity Circuit emblem plastered onto it - likewise, the Virus Army troops and vehicles have their V-shaped or rather, Commander Circuit shaped emblem adorning them.
- Slippy-Slidey Ice World: The Mountains.
- Smart Bomb: Screen Interrupt bombards all enemies on-screen with a Speed Blitz, though it is weak as an attack on its own.
- Smashing Hallway Traps of Doom: Crushers make an appearance in junkyard level. Better to be avoided.
- Spikes of Doom: Damaging spikes can be found all over the levels.
- Temporary Platform: Support Platform creates a Floating Platform beneath Kai, granting him another jump and potentially saving him from falling into any bottomless pits.
- There's No Kill like Overkill: You can keep wailing on enemies even after they enter a stunned state, which will eventually make them turn red (and unable to be grabbed) and explode.
- This Is a Drill: Crash the Break Circuit has a drill for an arm that he can launch forth to pull himself to another location, not unlike Kai's hookshot.
- Throwing Your Shield Always Works: Or rather, the enemies' shields. There's an achievement for doing this enough times.
- Throw the Mook at Them: An integral mechanic to the game is that Kai's grappling hook will grab defeated enemies, which he then hoists around. They can then be thrown at other enemies for massive damage. This is essential for Commander's final phase, as thrown enemies will instantly break his shield.
- Time Stands Still: Downplayed with the Gravity Freeze, which only freezes any tangible enemy that are nearby.
- Tragic Villain: The Commander Circuit's actions resulted in a lot of innocent bots dying, and had his plan succeeded, he would have killed all of the bots on the planet outside of the Guardians. However, it can't be said that he didn't get a raw deal when the other Guardians decided they were tired to abandoning planets. As Nega acknowledges, they could have just told him that the bots the Ark generated were self-aware, but the Guardians decided to bury him under the earth rather than face him, leaving him trapped for centuries, able to do nothing but stew in his anger towards being betrayed.
- Two Girls to a Team: Among the Circuits, Trace and Medley are the only girls.
- Underground Level: Ore Mines.
- Unobtainium: It goes by quickly, but Alph mentions in your first meeting that Kai's body is made of a metal called "xerotanium".
- What the Hell, Player?: Prior to the final stages, there is a huge glass canister containing a damaged robot in stasis. It can be attacked, which cracks it though it cannot be broken entirely. This causes Medic, who is monitoring the canister, to chastise Kai for doing so, eventually resulting in the player having to pay for the damages if you attack it enough times. You do get an achievement for doing this, though.
- Wrestler in All of Us: Heavenly Piledriver. Kernel busts out a lot of spinning lariats and powerbombs while under Commander Circuit’s control.
