- Badass Adorable: Could just be the pixel/art style, but you have to admit they're all pretty cute.
- Bottomless Magazines: While many weapons still have downtime, none of the mutants have been seen reloading their guns.
- Power at a Price: Crowns can be found and collected for further benefits, but at a price of something else (like the Crown of Guns dropping more guns, but at the price of removing normal ammo drops).
- Everyone Calls Him "Barkeep": With the sole exception of Y.V. (short for Yung Venuz), none of the mutants have a known name.
- I Love Nuclear Power: Collecting radiation allows the mutants to gain benefits such as more Health, ability to gain ammo upon kills, or even upgrading their active!
- One-Man Army: Being able to take down hundreds of enemies all just to reach a throne? Yeah.
- Portal Door: What everyone of the mutants finds after killing every enemy to go to another area.
- Starter Equipment: For most of them, it's a revolver of some type.
- Technical Pacifist: Going by the ending theme song, most of them would rather not fight even if they have to, except for...
- Token Evil Teammate: ...Plant, Y.V. and Robot.
- Was Once a Man: Currently, Fish, Steroids, and probably Melting are known to have been human before the apocalypse happened. It's unknown who else was once human in the group of mutants.
Fish's Throne Butt mutation changes his roll so that it has infinite duration and is fully controllable, allowing him to speed across the stage and run circles around his enemies. Fish's Ultra Mutations are Confiscate, which gives ammo drops a chance to replace the mini ammo chests with large ammo chests; and Gun Warrant, which gives him infinite ammo for seven seconds at the start of every level.
- And Your Reward Is Clothes: His B-Skin is unlocked by looping with every character at least once.
- Badass Grandpa: He was one day from retirement when the apocalypse happened so he must be considerably old in the present. This doesn't make him any less dexterous apparently.
- Boring, but Practical: Compared to the other mutants, Fish seems plain, but still ends up being useful in most situations with his combat roll and passive ammo gain boost.
- Bottomless Magazines: Gun Warrant gives him infinite ammo for a short period of time when starting a level, which is great on loops where enemies are overflowing.
- Eyes Always Shut: His sprite appears to show this, most of the time, but his eyes do open when going through portals as well as on the icons for 'Stress' and 'Recycle Gland'.
- Eyepatch of Power: His B skin has one.
- Funny Animal: He is an anthropomorphic fish after all.
- Improvised Weapon: He can use the guitar he plays in the character select screen as a weapon from the Campfire onward.
- Instrument of Murder: His guitar, which is about as strong as a sledgehammer but is much faster, making it one of the better melee weapons of the game. It can only be found by looping as him.
- Jack-of-All-Stats: Not outstanding in his offense or defense, but he has enough utility to go around.
- Retirony: He was one day from retiring from his job as a cop when the apocalypse happened. While he ain't dead yet, this is a roguelike...
- Unnecessary Combat Roll: Although in this case it gives Fish a decent speed boost, and with more control with Throne Butt.
Crystal's Throne Butt mutation causes her Crystal Shield to teleport her to the cursor, as long as its not within a wall. Reaching level Ultra allows Crystal to choose between Fortress and Juggernaut. Fortress gives her 6 extra max health, and Juggernaut allows her to walk around slowly while Crystal Shield is active.
- And Your Reward Is Clothes: Her B-Skin is unlocked by reaching the cursed variation of The Crystal Caves as her.
- Guide Dang It!: You can only access The Cursed Crystal Caves if you enter the end-level portal after defeating Big Dog whilst wielding a Cursed Weapon.
- Achilles' Heel: Despite being able to block a lot of the pain headed her way, Crystal's shield is bypassed by melee attacks (e.g. Assassins), energy shots (e.g. Laser Crystals), and explosions (e.g. Snipers' self-destruct).
- Attack Reflector: Crystal's active ability is to shield herself with a larger Crystal, reflecting most projectiles back at the enemy. (Which is a lot of them.)
- Barrier Warrior: Her main gimmick, and it's a darn effective one.
- Boring, but Practical: She's not the most exciting character but her durability will get you through the day.
- Lightning Bruiser: Becomes one with her Throne Butt, being able to teleport around the map while still being just as much of a Stone Wall as she usually is.
- Purple Is Powerful: She's the only purple crystal-based lifeform in the whole setting (aside from the enemies in the Cursed Crystal Cave), and is the only playable one.
- Rock Monster: A friendly one, but she's still a living, purple rock formation.
- Stone Wall: Her biggest strength to begin with, but it can be taken to truly ridiculous levels. She can reach a whopping 20 health allowing her to live through things no one else could withstand. (Except laser crystals.)
- Team Mom: One of her loading screen quotes simply reads "Family".
- Tele-Frag: Combining the Throne Butt and Gamma Guts mutations allows her to perform these by teleporting on top of enemies and killing them with the contact damage Gamma Guts provide.
- Teleport Spam: Her Throne Butt mutation allows her to teleport around the map at breakneck speed, even faster than Fish.
Eyes' Throne Butt Mutation increases the strength of his Telekinesis, to the point where bullets pretty much stop in their paths. Reaching level Ultra gives Eyes the choice between the two Ultra Mutations Projectile Style and Monster Style. Projectile Style changes Eyes' Telekinesis, making it drag any projectiles fired by Eyes to him, and letting go fires the projectiles in the direction they were traveling previously. Monster Style causes enemies to be pushed away passively, even if telekinesis is not active.
- And I Must Scream: Has a backstory, but no mouth to share it.
- And Your Reward Is Clothes: His B-Skin is unlocked by reaching The Pizza Sewers as Eyes.
- Guide Dang It!: You need to use an explosive weapon on a manhole cover which appears in the normal Sewers.
- Awesome, but Impractical: Projectile Style, big time. Its interactions with a lot of the more unusual weapons are fantastic and very fun(for example, using the Devastator turns you into a plasma snake and crossbow bolts can be used as melee weapons) but the need to micromanage your own projectiles while dealing with enemies being dragged towards you by the telekinesis can get overwhelming really quickly
- Body Horror: Not to Melting's level, but still there.
- Cool Shades: A variant. His B skin wears a pair of red-and-blue 3-D glasses, over top of his single large eye.
- Difficult, but Awesome: His passive is more or less useless for the majority of the game and his telekinesis isn't the easiest thing to use, but he's by far the best character against the Final Boss because of it, and intelligent use of it can make loops a whole lot easier to deal with.
- Eyes Do Not Belong There: Well, at least they are all on his head.
- Innate Night Vision: His passive.
- Mind over Matter: His active ability drags pickups, chests, and enemies to him, while reflecting projectiles slightly away from him. Made more powerful with his Throne Butt.
- One-Hit Kill: The biggest upside of Projectile Style is that it allows Eyes to pull these off against the final boss, which is otherwise a long and grueling fight. Projectile Style allows Eyes to stack up tons of projectiles before the fight starts, and as soon as the boss spawns, unleash them all in a massive blast that instantly destroys the throne. This is even easier to perform when looping, as the final corridor is filled with weapons lying around.
- The Speechless: Word of God says that Eyes has a backstory, but can't share it since he has no mouth.
- Secret Character: Unlocked by reaching The Sewers.
Melting's Throne Butt triples the size of his corpse explosions, allowing for large and often hilarious chain reactions. Upon hitting Level Ultra, Melting can choose between Brain Capacity and Detachment. Brain Capacity powers up Melting's corpse explosions to the point where it can blow up any living enemy with a current health of 5 and less, including undamaged enemies. Detachment cuts Melting's health in half in exchange for three extra mutations.
- And Your Reward Is Clothes: His B-Skin is unlocked by defeating The Nuclear Throne as him... but without using the Rhino Skin or Strong Spirit mutations.
- Body Horror: To the point where you can see his skeleton.
- Clipped-Wing Angel: He can be resurrected by a Necromancer, but doing so turns him into a mere Skeleton.
- Demolitions Expert: His active allows him to blow up bodies, with his Throne Butt and one of his Ultras improving the skill. Additionally, he's depicted in the art for Boiling Veins, and he's in fact encouraged to take it as, unless he has Rhino Skin, he'll always be under 4 HP to take advantage of explosives.
- Glass Cannon: Cannot afford to take any hits at all, but can deal a lot of damage with his ability to...
- Defeat Equals Explosion: ...explode the corpses of killed enemies for high damage. His Throne Butt causes 3 explosions per corpse instead.
- Magikarp Power: His passive causes him to gain extra rads from all sources, allowing him to gain more mutations quicker than other mutants can.
- One Hitpoint Wonder: While he does has 2 HP to start with, Melting is still this trope considering the amount of enemies who deal just 1 damage is low. His Ultra Mutation Detachment turns him into a literal one. Getting Rhino Skin (+4 HP) upgrades him to a two (or three) hit-point wonder.
- Only Mostly Dead: Implied with an update that changed his appearance slightly. The changelog reads "Melting now looks a bit less healthy." by which it means he lost quite a bit of color and thus more like a nearly dead being.
- Secret Character: Unlocked by dying for the first time.
- Taking You with Me: Melting can also blow up his own corpse. Not that it'll do the player any favors, but it's a way to squeeze an extra kill out of a run.
- Who's Laughing Now?: Can invoke this big-time once a player becomes skilled enough to Loop as him, and picks Brain Capacity. As noted above, this Ultra lets you blow up alive enemies so long as they're at low enough health. How many enemies do Loops have that count as weak enough for it? A lot.
Plant's Throne Butt Mutation causes its vines to instantly kill enemies standing in them if their health is lower than 33%. Reaching level Ultra allows Plant to choose between Trapper and Killer. Trapper multiplies the size of its snare by six, while Killer spawns Saplings whenever an enemy dies while standing in vines. Saplings home into other enemies and explode, damaging enemies and destroying projectiles in the process.
- And Your Reward Is Clothes: Its B-Skin is unlocked by defeating The Nuclear Throne as it in less than 10 minutes.
- Axe-Crazy: Really, REALLY likes murder.
- Blood Knight: As mentioned above, killing is all it has on its mind.
- Fragile Speedster: Plant's passive makes it innately faster than other mutants, but like most of the others would rather not take a hit.
- Green Thumb: Obviously, but Plant's active allows it to effectively stop enemies from moving with vines. With Throne Butt, the vines also gain the ability to kill any enemy under 33% health.
- Man-Eating Plant: Not exactly man eating with the apocalypse and what not, but still carnivorous and out for blood.
- Secret Character: Unlocked by reaching The Scrapyard.
- Speed Run: Is encouraged to do this to unlock its B-skin via reaching the Throne in 10 minutes.
- Guide Dang It!: Going to the Oasis is pretty much required, as it greatly cuts down the time to reach the Throne to make it doable.
Y.V. (Yung Venuz)
Y.V's Throne Butt upgrades his Pop Pop into Brrrrap, which fires four times at once at the cost of triple the regular reload time. Level Ultra gives Y.V the choice between Ima Gun God and Back 2 Bizniz. Ima Gun God gives Y.V an additional 40% attack speed increase, putting him at a total of 60% additional attack speed. Back 2 Bizniz gives Pop Pop an extra shot with no extra reload time or ammo wasted, or two extra shots if he has Brrrrap; in other words, three shots for the price of two at double the reload time or six shots for the price of three at triple the reload time. Both of his ultras take Y.V back to his crib, where he'll find his cousin Yung Cuz, a giant golden TV, and two massive golden weapon chests that spew fifty weapons from up to six difficulties higher.
Unlike the rest of the cast, Y.V has money to burn, so he starts out with a golden revolver instead of a regular revolver. It not only looks fancier but actually has a slightly higher rate of fire.
- And Your Reward Is Clothes: His B-Skin is unlocked by getting a starting Golden Weapon for every other character.
- Berserk Button: If this comic and one of his loading screen tips ("no popo") has any indication, he really hates cops.
- Blood Knight: Y.V likes shooting things, not that one would expect anything less from the god of guns.
- Cloudcuckoolander: At least in comparison with the other characters. Consider that he's from a different planet and really has no reason to reach the Throne except for the fun of it.
- Character Blog: His Twitter account. He dreams to be verified someday...
- Cyclops: A white triangular one.
- Double Tap: The active of Y.V. is a really unrealistic version of this trope (though possibly justified considering he's a Gun God), as Y.V. shoots the 2 projectiles at the same time. With Throne Butt, the Double Tap is now a Quadruple Tap. Too bad it also dramatically reduces the fire rate of the weapon when used.
- Grievous Harm with a Body: The sheer knockback power from Y.V.'s active causes the dead bodies of enemies to file across the level and hit other enemies, possibly killing them as well.
- Guide Dang It!: You need to use the Screwdriver on a specific car prop, the one with gold trims, in The Scrapyard. The screwdriver only spawns in the Desert, meaning you have to cart it all the way through the sewers and the scrapyard until you find the car. And make sure you don't hit the wrong car, or it'll explode and kill you
- Money Fetish: Fitting when he's literally the all-seeing eye.
- More Dakka: Venuz's passive allows him to shoot guns considerably faster, useful with his active.
- No Name Given: Inverted, as he's the only one with a known name.
- Odd Job Gods: He's a Gun God, giving him all sorts of unfathomable gun-related powers that he only seems to use two of. According to Word of God this also makes him immortal; instead of dying when his HP hits 0, he simply teleports away out of frustration.
- Screw This, I'm Outta Here!: As mentioned above, Y.V. is immortal, so upon reaching 0 HP, he just teleports back home instead of dying.
- Secret Character: Unlocked by reaching his mansion.
- Shout-Out: He first appeared as a boss in Vlambeer's previous title Gun Godz.
- Taunt Button: Pressing B while playing as Y.V. causes the screen to shake and an airhorn sound to play.
- Tranquil Fury: His B skin has him taking a meditative lotus position, but he's exactly as deadly as he was before.
- Vocal Dissonance: Those who know him from Gun Godz will be surprised by his comparatively high-pitched voice in this game versus the deep gravely one he had in the former.
Steroids' Throne Butt Mutation give him a chance to gain ammo for one of his weapons while firing the other, with a significantly greater chance to gain ammo while firing both. reaching level Ultra allows Steroids the choice between Ambidextrous and Get Loaded. Ambidextrous causes all weapon chests to increase two copies of the same weapon, and large weapons chests to contain four weapons instead of three. Get Loaded causes all ammo chests to contain ten mini-ammo chests, with two chests for each weapon type.
- And Your Reward Is Clothes: His B-Skin is unlocked by defeating The Technomancer as him.
- A-Team Firing: Has poorer accuracy than the other mutants. Of course, he makes up for it by starting with more ammo and his active.
- The Big Guy: Easily the strongest mutant in the group. His loading screen blurb notes that he could do pushups forever.
- Boring, but Practical: His Dual Wielding active combined with his innate rapid fire perk makes revolvers and assault rifles, which are otherwise lackluster weapons, much more viable than machine guns in terms of stopping power.
- Bottomless Magazines: A downplayed variation; his Throne Butt mutation allows him to randomly generate extra ammo for his weapons while firing, the effects of which are made more frequent by firing both weapons at oncenote . Combining this with the Recycle Gland (for bullet-based weaponry) and Lucky Shot mutations ensures he won't be running out of ammo for a long time.
- Dual Wielding: Steroids' active lets him use both of his weapons at the same time, allowing for creative combinations. A sniping weapon in one hand and a melee weapon in the other?
- Dumb Muscle: Averted. He was a brilliant scientist who predicted the apocalypse before everyone else, and so beefed himself up using steroids to prepare. He also managed to retain the most of his humanity.
- Full-Frontal Assault: As the only mutated character who has most retained his human features, his nudity is more pronounced. Although he seems to be missing certain features.
- Genius Bruiser: Was once a scientist and still reads books in his spare time. He can also do pushups forever.
- Half-Dressed Cartoon Animal: Oddly enough, despite being the most human-looking of all the mutants, his B-Skin consists of him wearing a gray tank top, but no pants.
- More Dakka: All of his weapons have rapid fire enabled, even the melee weapons. This does mean that it's easier to run out of ammunition when playing as Steroids, however, unless you take his Throne Butt mutation in tandem with other mutations that help (re)generate ammo (see Bottomless Magazines above).
- Properly Paranoid: Buffed himself up in preparation of the apocalypse. Good thing for him, it happened.
- Secret Character: Unlocked by reaching The Labs.
- Super Strength: He could do pushups forever if he wanted to.
Robot's Throne Butt Mutation doubles the effect of eating weapons. Reaching Level Ultra allows it to choose between Refined Taste and Regurgitate. Refined Taste increases the drop rate of powerful weapons by removing all of the early-game weapons. Regurgitate gives Robot a chance to spawn a chest on top of itself whenever it eats a weapon.
- And Your Reward Is Clothes: Its B-Skin is unlocked by eating a Hyper Weapon (Hyper Slugger, Hyper Launcher, or Hyper Rifle).
- A.I. Is a Crapshoot: Its loading screen messages include quoting HAL 9000 and saying "Kill all humans" in hexidecimal so chances are this is the case.
- Item Caddy: Its passive gives Robot better weapons, its active lets it eat them.
- Extreme Omnivore: Robot can eat its own weapons for extra ammo and health. Throne Butt doubles this effect.
- Odd Name Out: Justified since Robot is not actually a mutant like the others, but is still accepted of one of them.
- Randomly Generated Loot: Robot's passive lets it find better weapons than other mutants in the same area. Every area has a loot table associated with it, causing more weapons to spawn as players go further into the game. Robot's passive ability causes it to use the loot table of the next area, which means that it has more chances to get a rare weapon. Refined Taste plays with this trope even more by completely removing any weapon that would drop on stages prior to 3_1, meaning that weapons that will be worthless by the end-game such as Screwdrivers, Sluggers and Pop Guns will never be dropped.
- Robot Buddy: Although more of an independent entity than a buddy.
- Secret Character: Unlocked by reaching The Frozen City.
- Shout-Out: Robot was a playable character in Super Crate Box, a game also made by Vlambeer, the developers of Nuclear Throne.
Chicken's Throne Butt Mutation makes her thrown weapons pierce through enemies. Reaching level Ultra allows Chicken to choose between Harder to Kill and Determination. Harder to Kill resets Chicken's bleedout timer whenever she kills an enemy, while Determination makes her thrown weapons teleport back to her secondary weapon slot.
Chicken starts out with a sword instead of a revolver. Chicken loves her sword.
- And Your Reward Is Clothes: Her B-Skin is unlocked by reaching The Sewers on Hard Mode as her.
- Awesome, but Impractical: Throwing weapons is a cool thing to do, but it's impractical in serious firefights, you're going to have to re-retrieve the weapon, and you're better off shooting unless you're out of ammo. Her Determination Ultra averts this a bit, as it brings thrown weapons back into her inventory, allowing the player to take the risk.
- Chekhov's Boomerang: Her Katana. Unlocking Chicken's secret weapon requires the player to leave her Katana behind in the starting Desert level by throwing it away, then successfully looping the game and reaching the Desert again, at which point the Black Sword will be lying on the ground. This has a chance of going awry if the Level 1-1 portal manages to suck the sword in at the last minute.
- Cool Sword: Starts with one instead of a revolver like the other mutants.
- Determinator: So determined, even decapitation takes a long time to slow her down. Her "Harder to Kill" Ultra Mutation takes this Up to Eleven.
- Funny Animal: Like Fish, but as a chicken instead of a fish.
- Katanas Are Just Better: An aversion: the Chicken Sword is among the weakest weapons in the game, having the same damage as a Screwdriver with a lower firing speed but larger swing arc. The Black Sword plays it straight, though.
- Precision-Guided Boomerang: One of her Ultra Mutations, "Determination", will cause all thrown weapons to return to her offhand slot after a short delay, making it useful for pure melee runs or when you don't want to get rid of an empty gun just yet.
- Secret Character: Unlocked by reaching The Jungle.
- Guide Dang It!: You need to interact with a specific prop in The Frozen City (the frozen Corpse Flower). Even then, however, you will need a specific mutation (Last Wish) to activate the portal.
- Throwing Your Sword Always Works: Her active ability. Bonus points for actually being able to throw a sword.
- Time-Delayed Death: Chicken's passive. When she "dies", her head simply instead falls off. If she can obtain a source of healing before she bleeds out, Chicken will grow her head back on and continues to live.
- Toothy Bird: she's got a lot of molars in that beak.
Rebel's Throne Butt Mutation increases the firing rate of her allies, almost doubling it. Reaching level Ultra allows her to pick between Personal Guard and Riot. Personal Guard increases the health of her allies and causes two allies to be spawned at the start of a level. Riot makes it so that two allies spawn at once when her ability is used.
- And Your Reward Is Clothes: Her B-Skin is unlocked by defeating Mom as her.
- The Atoner: Several of her loading screen tips imply that she regrets her days as a bandit.
- Badass Longcoat: Her B skin has her trade her signature scarf for a winter coat. Her allies keep the scarf, though.
- Bandage Mummy: She is covered in bandages, much like all of the other bandits.
- Blood Magic: Possibly how she creates her allies.
- Cast From Hitpoints: Her allies cost her health to spawn, which is implied to be because she uses her blood to create them.
- Healing Factor: She passively gains health upon entering a portal.
- HeelFace Turn: Was once a normal bandit, but something made her change her ways.
- Long-Lost Relative: She has a brother whose current location is unknown. It's actually Big Bandit, the boss of the Desert Wasteland. She even has special dialogue after killing him.
- Scarf Of Asskicking: Has a long blue scarf. She likes it a lot.
- Secret Character: Unlocked by looping to 0-1 after beating The Nuclear Throne.
An amorphous being of living radiation energy, Horror is a character for the player looking for flexibility. Horror's passive ability allows it to choose from five mutations instead of four when it levels up, giving it a greater chance of getting what it wants. Horror's active allows it to use the radiation it has gained from killing enemies to fire a powerful beam attack, destroying projectiles and dealing high damage to enemies hit at the cost of permanently losing any radiation that doesn't hit enemies.
Horror's Throne Butt speeds up the time it takes for Horror's Radiation Beam to charge and heals Horror when the beam is used for long periods of time. Reaching level Ultra allows Horror to choose between Stalker, Anomaly and Meltdown. Stalker causes enemies that drop rads to explode into radiation, shooting projectiles in all directions that act like it was fired by Horror's radiation beam, with more projectiles the more radiation the enemy dropped. Anomaly causes the level ending portal to open when the total health of all enemies left is 140 or lower, as opposed to when all enemies are dead. Meltdown doubles Horror's rad capacity, allowing it to fire its radiation beam for twice as long.
- And Your Reward Is Clothes: It's B-Skin is unlocked by defeating the Hyper Crystal as Horror.
- Death Ray: Horror's active is to literally spill out radiation to kill enemies.
- Defeat Means Friendship: How you unlock Horror.
- Energy Beings: In this case, a radiation being.
- Guide Dang It!: Nothing in the game hints towards the method required to unlock Horror.
- HeelFace Turn: It was once one of the Palace Guardians protecting the Nuclear Throne.
- Purple Is Powerful: Its B skin makes it the same shade of purple as the level portals.
- Secret Character: Unlocked by defeating it.
- Guide Dang It!: Horror will only appear as an enemy if you skip two radiation canisters. This is especially frustrating if explosions from a portal or enemy break them anyways.
- Skill Scores and Perks: Horror's passive gives it an extra mutation option, making it more likely to get what mutations it wants.
A character designed for the experienced player, Rogue starts the game being chased by the Inter Dimensional Police Department, causing powerful enemies to spawn in on the map at random, coming in more and more powerful waves the longer the game goes on. Thankfully for Rogue, she can turn the heat on the IDPD in the form of the Portal Strike, which allows Rogue to target an area of the screen which will within seconds become bombarded with a line of powerful explosives. In addition Rogue's blast armour creates a small explosion around her when she takes damage, meaning melee enemies will be in for quite a surprise when they come at her.
Rogue's Throne Butt Mutation increases the damage dealt by the Portal Strike, and reaching level Ultra allows Rogue to choose between Super Portal Strike and Super Blast Armor. Super Portal Strike doubles the ammo you can carry for Portal Strike and gives you double the ammo from Portal Strike ammo containers. Super Blast Armor powers up her Blast Armor, causing it to create four explosions instead of one.
Unlike the rest of the cast Rogue starts out with a unique Rogue Rifle, which fires in two-shot bursts with a high fire rate.
- And Your Reward Is Clothes: Her B-Skin is unlocked by defeating the I.D.P.D. Captain as her.
- Counter Attack: An explosion of energy spontaneously forms around Rogue when she takes damage, damaging nearby enemies. Rebel's passive was changed because of this.
- Defector from Decadence: As far as we know.
- Difficult, but Awesome: Her single biggest quality by far. She starts out with an awesome gun and an insanely powerful active ability but the constant pressure applied by the I.D.P.D, including the dreaded Shielders, is more than most players can bear.
- HeelFace Turn: Used to be one of the I.D.P.D., but she defected after they abandoned Lil' Hunter after he failed a mission.
- Hoist by His Own Petard: Rogue is not immune to the damage of the Portal Strike, and hitting yourself with it is almost guaranteed to kill you dead, unless you have Boiling Veins.
- Kill Sat: The Portal Strike, which bombards a large areas for devastating damage.
- Secret Character: Unlocked by reaching The Nuclear Throne. That is, defeating it for the first time.
- Token Human: A result of being from the same parallel universe the IDPD are from.
- Weapon of Choice: Starts with a 2 round burst IDPD gun instead of the standard revolver.
- We Used to Be Friends: Used to be good friends with Lil' Hunter, and his being abandoned by the I.D.P.D is what caused her to betray them in the first place.
- You No Take Candle: Speaks Trashtalk like the mutants, but according to Word of God it's pretty broken, like she's still learning the language.
Skeleton starts with 1 out of 4 maximum HP, and has less accuracy and movement speed. His active ability lets him fire without using ammo, but there is a chance that the shot will deal damage to him instead.
Skeleton's Throne Butt reduces the chance of his Blood Gamble hurting him, and reaching Ultra allows Skeleton to choose between Redemption and Damnation. Redemption removes all of Skeleton's mutations, turns him back into Melting, and lets him pick nine new mutations plus one of Melting's Ultra Mutations. Damnation significantly reduces reload time while Blood Gamble is being used.
- Dem Bones
- Guide Dang It!: The method to unlock him is even more obscure than for Horror, and to make matters worse, his existence was not even hinted at in the changelog of the update that made him playable.
- Joke Character: Skeleton is horribly slow and inaccurate, and his active has a chance of hurting himself, with his Throne Butt merely reducing the chance rather than eliminating it. Rather tellingly, the hardest achievement in the game is getting him to live long enough to reach Level Ultra.
- Magikarp Power: Of a sort. Inheriting half of Melting's EXP definitely allows him to catch up a bit faster.
- One Hitpoint Wonder: Starts off with just 1 HP, in addition to having a lower maximum.
His Throne Butt makes all toxic gas, not just what he creates with his ability, spread further and faster. Upon reaching Ultra, Frog gets to choose between Distance and Intimacy. Distance makes all rads (whether from enemies or canisters) emit toxic clouds, one per rad. Intimacy makes it so that Frog constantly lets out gas as he moves, and also changes his active to constantly release gas instead of charging a big cloud of it.
- Gasshole: If the loading screen tips are any indications, he seems to be unable to keep his gas inside.
- Guide Dang It!: If you thought Skeleton's recruitment was bad, Frog's is worse.You have to damage Mom using a Golden weapon at least once. Then, you have to retrieve the Frog Pistol she dropped upon death. After that, you have to go to a Crown Vault and store it inside the Vault Chest. Play as a different character later in a different run and get the Frog Pistol, now turned Golden. The weapon is stored into your loadout once you exit the Crown Vault.
- HeelFace Turn: Similar to Rebel in that he's a playable character of a standard enemy.
- Poisonous Person: Just like all Ballguys.
- Stance System: His Ultras definitely feel more like two different playing styles than most other characters, with Distance focusing on...well, keeping distance from your enemies, and Intimacy being about getting up close and personal.
- Taking You with Me: Explodes into a burst of projectiles on death in the same way an enemy Ballguy would.
- Too Fast to Stop: While he's not fast per se, he's unable to stand still unless you hold right-click.
Enemies:This section is organized by areas where each enemy is introduced.
- Elite Mook:
- Toxic Ballguys, which are created when a Ballguy comes in contact with radiation made by the toxic barrels and Mom.
- Buff Alligators, stronger Alligators that uses a weapon akin to the Flak Cannon.
- Faking the Dead: Assassins (which debuts here but are mainly associated with The Scrapyard) pretend to be dead and are activated when you pass by them.
- Mook Maker: Big Green Rats, huge rats that spawns Green Rats (which is a weaker rat that doesn't leave a corpse); after spawning a certain number of Green Rats, they rush at the player and explode.
- Zerg Rush: The main method of attack of the Rats.
- Mythology Gag: The enemies are all borrowed from Gun Godz, YV's debut game.
- Big Creepy-Crawlies: The Crystal Spiders.
- Elite Mook: Lightning Crystals, which discharges lightning like the lightning weapons instead of shooting energy beams.
- One-Hit KO: Touching any Crystal is an instant kill.
- Tele-Frag: The cursed versions of the crystals can randomly teleport, which results in this if it teleports into you considering that touching crystals is a one hit kill.
- Car Fu: The Snowbots can pick up cars, and will rarely throw them, which results in an explosion. Note that a thrown car does touch damage and then explosion damage, which could result in a death even with Strong Spirit.
- Elite Mook: Golden Spider Tanks, that not only have a faster reaction time than normal ones, but also shoots a missile among the bullets.
- Unique Enemy: Bandits are dressed in snow gear in this level, and only appear around the Crown Vault or if one of the snowmen are destroyed.
- Mook Maker: Necromancers revives corpses into Freaks. They can also revive Melting into Skeleton.
- Mix-and-Match Critters: The Freaks appear to be fusions of the playable mutants; The basic Freak is a fusion between Fish and Eyes, the Explo Freak is a fusion between Melting and Plant, and the Rhino Freak is a fusion between Crystal and Steroids, with the Rhino Skin mutation.
- Zerg Rush: A majority of enemies in this area attack by rushing you down.
- Energy Beings: All of the non-IDPD enemies.
- Badass Normal: The IDPD are made up of normal humans that are just as threatening, if not moreso, than the mutants of the wasteland.
- Badass Abnormal: The Inspectors and Elite Shielder definitely has strange powers to go with their weapons.
- Bilingual Bonus: If you listen closely to some of their voice clips, the units appear to be speaking garbled and sped-up Finnish.
- Body Horror: The IDPD units in loop 3 turns into twisted mutants that's a cross with the Lab's Freaks.
- Elite Mook: The three IDPD types has elite counterparts that are much tougher.
- Evil Counterpart: The Grunts copy Fish's rolling, the Inspectors uses Eye's telekinesis, and the Shielders uses Crystal's shielding. The Elite versions are not just stronger, but also uses the Throne Butt versions of their abilities.
- One-Hit KO: The police vans that appear in the loops is one if it hits you. Which means you need to time your attempts to go to the IDPD Headquarters just right.
The boss of the Drylands, Big Bandit is the leader of the bandits and doesn't take too kindly to strangers mowing down his men. He comes equipped with a big machine gun and a bad disposition.
He spawns on 1_3 when the player kills 10% of the enemies present on the map, or on any stage of the Drylands if the player opens all of the chests without killing an enemy. Looping causes two Big Bandits to spawn for every every time the player has looped, and makes all of them more aggressive.
- Bandage Mummy: Like the rest of the bandits.
- Bull Fight Boss: A risky but effective way to kill him with a melee weapon. He will attempt to charge into the player if they're close to him, and being hit by his charge is almost guaranteed to instantly kill the player. At the same time, hitting him with a melee weapon during the charge causes him to take damage very rapidly due to the way the hit detection works, to the point where a single swing of the shovel or sledgehammer can kill him outright.
- The melee hit detection tactic got nerfed in Update 99. Have fun!
- I Shall Taunt You: Says in trashtalk, "HYÄ DÄ HU" ("Lost dead weakling!"), laughs, and spits at you when you die against him.
- King Mook: He is the leader of bandits and fights in a somewhat similar fashion to his men.
- Large and in Charge: Twice the size of a regular bandit, and their undisputed leader.
- There Was a Door: He will charge through any wall between you and him should you run out of his line of sight. Even if the wall is a single block and he could just as easily walk around it.
- Warm-Up Boss: As the first boss in the game, he has far less tricks up his sleeve than the later ones. You're still best off not underestimating him, though.
- Wolf Pack Boss: Becomes one upon looping, as it causes multiple Big Bandits to spawn.
The boss of the Scrapyard, the humongous, lumbering Big Dog spends of his time sleeping and doesn't like intruders disturbing his slumber. He fights with a large amount of bullets and homing rockets.
Big Dog is found sleeping on 3_3, and wakes up if dealt enough damage to or if the player gets too close. On loops, the rockets fired by Big Dog will fire bullets as well.
- Everything Is Better With Spinning: He spins to fire bullets.
- Friendly Fireproof: Part of what makes his battle dangerous is this, as enemies can shoot through him to you. This is dangerous as he can act as a meat shield to snipers that constantly puts pressure on you.
- Hellhound: Not a very usual-looking one, but the inspiration from the Cerberus is totally there.
- Promoted to Playable: Was playable as an April's Fools joke during the 1st of April and for about a week after.
- Taking You with Me: Sets off several explosions when killed, which can kill you if you stand too close to it.
The boss of the Frozen City, Lil' Hunter is member of the I.D.P.D. who has been driven to insanity by the harsh conditions of the wastelands. Armed with a gun and a jetpack, he stalks the Frozen City in search of worthy opponents.
Lil' Hunter is found on 5_3, and unlike the other bosses is not spawned by the player. Instead he appears after a certain amount of time has passed, swooping down on the player like a hawk. Looping decreases the amount of time it takes for him spawn.
- Flunky Boss: Calls in waves of I.D.P.D Grunts during the fight to assist him, allowing him to fire away at the player from a distance as they're left to deal with the mooks. This gets especially dangerous during loops as he can call in stronger reinforcements, including the dreaded Elite I.D.P.D
- However, he's a sitting duck while he's calling in the Grunts, so a smart player will take the opportunity to fire off a shot or two during the teleportation animation.
- "Get Back Here!" Boss: He uses his jetpack a LOT, flying off into the air to reposition himself should you leave his line of sight. He also dodges like crazy, making him hard to hit.
- Glass Cannon: He moves fast and can deal a lot of damage, but goes down quickly. (For comparison, Big Dog, the previous boss, had 300 hit points. Lil' Hunter only has 120.)
- I Call It "Vera": The gun of Lil' Hunter is named Lil' Gunther.
- I Shall Taunt You: He cackles maniacally upon killing the player.
- Taking You with Me: Defeating him causes his jetpack to malfunction, causing him to go rocketing into a random direction before exploding. This can kill you and he'll certainly try to make that happen.
- Tragic Villain: He has the saddest backstory in the game, according to Word of God.
- Sanity Slippage: Used to be an I.D.P.D. agent and Rogue's friend. Radiation, isolation and the harsh conditions of the wasteland have deteriorated his mind to the point he doesn't remember his past as an officer nor Rogue.
- We Used to Be Friends: Used to be a close friend of Rogue. Then he went insane after failing a mission and being stranded by the IDPD.
The Nuclear Throne
The boss of the Palace, and the final boss of the game, they sit on the titular nuclear throne, waiting patiently for those that would challenge their authority. Or so you would think; the final boss is actually the throne itself.
They are found on 7_3, where they sit at the end of the long corridor leading to the nuclear throne. Upon loops they gain significantly more health.
- Advancing Boss of Doom: They will move forward as the fight drags on, eventually reaching the back of the room. Touching them is an instant kill, meaning that reaching the wall is a death sentence unless you have an explosive weapon or the Hammerhead mutation.
- The Dog Was The Master Mind: A chair was behind everything!
- Eldritch Abomination: The Throne's true form, complete with powers capable of distorting reality itself.
- Flunky Boss: If its attacks touch the statues in the arena, they turn into Guardians.
- One-Winged Angel: After taking down the Throne in 7-3, it returns for revenge in 0-1 as Throne II.
- Spider Tank: The Throne becomes one during the fight in 7-3.
- Walking Spoiler: The true identity of the final boss is the throne itself, as opposed to the skeleton sitting on it.
The loop-exclusive boss of the sewers, Mom is a ballguy matriarch who personally takes up the task of protecting her brood. She fights the player by spewing balls of poisonous gas and laying clutches of eggs that hatch into ballguys, who can turn into the far more dangerous Toxic ballguys if they touch the poison created by Mom.
- Combat Medic: Mom, in a sense, since the poisonous gas she creates heals both her and the toxic ballguys she can spawn.
- Evil Sounds Deep: Has the deepest voice of all the ballguys, which is easiest to hear when she laughs at your death.
- Flunky Boss: Fighting her means having to manage her constant supply of ballguys as leaving the eggs alone is sure to get you overwhelmed.
- Large and in Charge: Way bigger and uglier than regular ballguys and the strongest one by far.
- Mook Maker: Constantly spawns ballguy eggs.
The loop-exclusive boss of the Crystal Caves, the Hyper Crystal is large Laser Crystal that creates and controls regular Laser Crystals.
- Flunky Boss: Summons Laser Crystals to shield it during battle.
- Large and in Charge: Much larger than regular Laser Crystals and far more powerful than they are.
- The Speechless: Creepily averted. You would expect something that is literally just a crystal to have no voice at all, but if you listen carefully, you can hear it screaming and it even laughs at you when it kills you.
- There Is No Kill Like Overkill: It deals 200 damage on contact, which kills even the healthiest mutant ten times over. Word of God states that touching the Hyper Crystal is the equivalent of having that particular limb stretched almost infinitely into the next dimension, hence the ridiculous damage.
The loop-exclusive boss of the Labs, the Technomancer is a Necromancer piloting a machine that empowers their abilities. The Technomancer can not do anything to hurt the player on their own, but they do have the ability to revive fallen foes as Necromancers, who in turn can revive other enemies as Freaks.
The boss and captain of the I.D.P.D Headquarters, a loop exclusive secret area. She fights the player by charging at them, teleporting rapidly around the arena, and firing projectiles at them. Lots and lots of projectiles.
- Authority Equals Asskicking: She's just as brutal as the Nuclear Throne itself, if not moreso.
- Badass Cape: She uses it as a defensive and offensive tool.
- Bilingual Bonus: She seems to be speaking Finnish, like the rest of the IDPD.
- Bullet Hell: Pretty much rivals the final boss in this sense, and that's definitely saying something.
- Foreshadowing: The cutscene after the credits of the normal ending shows her watching the winning character sitting on the Throne, hinting that there's much more to the game than merely beating the Throne.
- Large and in Charge: She's the biggest human character in the game.
- True Final Boss: Beating her gives you an alternate ending, but as of update #93 it remains as much of a Gainax Ending as the unfinished normal ending cutscene.
- What Happened to the Mouse?: In the third loop, the IDPD start mutating and their vans explode, preventing you access to the headquarters and her battle. Either these vans blow up to keep the mutated mooks from going back to the HQ or something horrible happened.