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Bonus Dungeon

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"Look, it's the extra dungeon for after you beat the game. Good luck!"

Sometimes, hardcore gamers, especially fans of RPGs, feel cheated that the popularization of video games has led to a lessening in difficulty. Enter the bonus dungeon, a difficult optional dungeon that's usually not directly connected to the main game's story. The bonus dungeon offers an additional challenge near the end of the game or after.

The bonus dungeon will be bigger, badder, and with more levels than the other stages in the game. It will be filled with new monsters. Sometimes, game designers cut corners by making all the monsters here simple recolors of common monsters, but with higher stats.

This is where the Superboss usually lives. Sometimes, the Infinity +1 Sword will be waiting at the bottom.

Compare Secret Level. Often a Brutal Bonus Level.

Since these are usually secret levels, expect the examples to contain spoilers.


    open/close all folders 

  • Ittle Dew has a couple:
    • The Master Cave is home to the game's very hardest puzzles. It even requires you to use techniques you never need anywhere else.
    • The Compost Crypt was added after launch in a Halloween update. It features more of a balance between combat and puzzles. Notably, the enemies can't be frozen, making them immune to a cheap freeze-then-smash kill.
  • The Legend of Zelda:
    • The Legend of Zelda: A Link to the Past: There's an extra dungeon in the remade GBA version. Players can't access the dungeon until they completed the multiplayer Four Swords game. Inside the dungeon is 4 areas with very tough puzzles and color swaps of some of the bosses Link fought previously, along with new behavior patterns. Beating all 4 bosses opens the way to fighting 4 clones of Link from the Four Sword, each Link bearing a different color and abilities that mirror Link's. Beating these bosses only gets you statistics of your game data, so it's nothing but bragging rights.
    • The Legend of Zelda: Link's Awakening DX has the Color Dungeon, which is only accessible by playing the game on a Game Boy Color. It includes color-based puzzles, such as colored switches and enemies that are only distinguishable by their tunics having to be beat in a certain order. For winning, you get either a Red or Blue Tunic, which puts you permanently under the effect of a Piece of Power (increased speed and attacks send enemies flying and do double damage) or a Guardian Acorn (double defense), respectively. This dungeon is also present in the Switch remake.
    • The Legend of Zelda: Ocarina of Time has the Gerudo's Training Ground, out in their outpost, which consists of solving puzzles in different rooms to collect keys. These keys are used in a maze to get the Ice Arrows. While rumors suggested that the cave could be made Unwinnable by Design under certain conditions, the dungeon is always solvable.
    • The Legend of Zelda: Oracle Games: The games include special dungeons, available only in linked games. They're both called the Hero's Cave, but their challenges and rewards differ based on which order the games were played in. The one in Seasons replaces the mini-dungeon of the same name that would give you the sword in an unlinked game, while the one in Ages just appears on an otherwise-blank wall.
    • The Legend of Zelda: The Wind Waker has a number of multi-level gauntlets. Only one of them (Savage Labyrinth) is required to finish the game, the rest are hidden on islands around the Great Sea. And the required one only has the necessary Plot Coupon past the 30th floor, meaning that the remaining 20 floors are bonus content.
    • The Legend of Zelda: Twilight Princess has two major ones (though one of them is exclusive to the HD remake) and a small handful of minor ones:
      • The Cave of Ordeals, a gauntlet of monsters similar to the ones in The Wind Waker, with monsters ranging from a single one of the weakest monsters in the game, to three of the strongest and fastest monsters at the same time. If you can reach the bottom, you'll find an inexhaustible supply of a potion that fills your health gauge and temporarily boosts your offensive capabilities, making you unstoppable in combat. Although if you can reach the bottom, you likely won't need that kind of advantage, even against the final boss. You can go back to it afterwards and find the the difficulty has increased.
      • The HD remake adds the Cave of Shadows, which is only accessible with the Wolf Link amiibo. You're stuck in Wolf Link form the entire time, and the reward for beating it is a wallet upgrade letting you hold 9,999 rupees and your Wolf Link companion in The Legend of Zelda: Breath of the Wild having the same amount of hearts you beat the cave with. However it's not necessary to beat the entire cave if you just want your hearts saved to the amiibo.
      • Lantern caves. They are huge complexes of tunnels that require your lantern to light the way while you fight your way past monsters and pitfalls, collecting an assortment of goodies on the way.
    • The Legend of Zelda: Spirit Tracks has several optional, secret locations that are reachable only when gathering the pertinent Force Gems via sidequests. The most prominent of them is the Lost at Sea Station, which mimics the setting of the Temple of the Ocean King from Phantom Hourglass.
    • The Legend of Zelda: Tri Force Heroes has the Den of Trials, which mixes all of the previous seven worlds into an extra big 40 floor dungeon and ends with a boss battle with Shadow Link.
    • The Legend of Zelda: Breath of the Wild: The DLC has the Trial of the Sword; an incredibly difficult challenge that, if one succeeded, permanently gives the Master Sword the bonus it usually only gets near Guardians, Malice or Ganon.
  • Ōkami features a particularly evil example. In different areas of the overworld there are three caves that are home to (slightly) upgraded versions of a previous giant demon spider boss. Defeating them earns a reward, but you can then return to the same cave later to find a demon gate eerily sitting there. Going through forces you to battle wave after wave of superpowered regular enemies. Even the lowliest of Mooks can waste you with a couple of hits in these battles (and you have to go through 10 of them to get the reward) and have HP that would make some of the late-game bosses jealous. These battles could be considered a refreshing change of pace compared to the general easiness of Okami if not for their sheer sadism. The most difficult cave has you face several minibosses from the past in groups, usually two or three at a time. Including Waka and two possessed Raos.
  • The Tower of Druaga, in the Namco Museum Vol. 3 Compilation Re-release on the Playstation, had two secretly unlockable 60-floor towers both harder than the original: "Another Tower" and "Darkness Tower", the latter having many new treasures. The Famicom and Game Boy versions had a different "Another Tower."

    Card Games 
  • Yu-Gi-Oh! Reshef of Destruction has the Hall of Eternity, which is a single room where you can battle Yami Yugi, Yami Marik, Yami Bakura, Dark Joey/Jounouchi, Noah Kaiba, Pegasus, Shadi, and Paradox, all of whom are powerful superbosses who require you bring your A-game when you duel them.

    First-Person Shooter 
  • The first two Descent games had several secret levels, where the difficulty jumps from the regular levels' Nintendo Hard to Ninja Gaiden levels. Level 30 (secret level 3) of Descent on Insane difficulty is nearly impossible to beat. There's also the second secret level, where to rescue the hostages and get 100% Completion, you have to shoot the doors from the inside while being assaulted by endless waves of Invisibility Cloaked Hulks and Drillers.
  • E.Y.E: Divine Cybermancy has cm_cu_minos, which until the recent patch was the only included "custom" mission. A large and semi-mazelike map whose floor is full of holes, forcing you to take it slowly and carefully. The practically constant monster spawns ensure that even restocking ammo can be a challenge. The missions range from the innocuous (destroy a few harmless beacons or kill x regular monsters) to the outright cruel (slay the Master-rank Deus Ex, which easily soaks more than ten shots from a gun that three-shots its lesser brethren, two-shots gunships, and one-shots everything else). And it's always full of Kraakanaguls, the big guys that dual-wield warhammers. Sometimes one of your missions is to kill all of them. Your reward? Whatever EXP and money you got from doing the mission, plus a little extra cash on top.
  • Marathon Infinity has the vidmaster levels. These levels are accessed through a secret area on the last level, and basically put you in three of the hardest levels of the series (One from each game), pitted against the hardest form of each enemy. The reward: Bragging rights.
  • Medal of Honor Underground featured a campaign after the main game. Players reprised the role of Jimmy Patterson, hero of the first game, as he stormed the castle of a mad Nazi scientist. The castle was replete enemy types, including attack dogs operating armored vehicles and automatons made from suits of medieval armor. Patterson even constructs his own automaton - a man-sized nutcracker.

    Hack and Slash 
  • The PlayStation translation of Gauntlet Legends had several of these, including one-level versions of every stage that got cut from the PS1 version. However, after all the bonus dungeons composed of stages cut from the arcade version, the game had as its final hidden stage... the building the developers made the game in. The sole enemy? A giant hamster, the development team's "mascot."
  • Grim Dawn has five challenge dungeons scattered through the game world. Each one requires a Skeleton Key to enter and does not allow you to leave through the entrance or open a riftgate out, requiring you to either defeat the Superboss or die trying. The dungeons are filled with traps, dangerous environmental effects, sub-bosses, and a high spawn rate for King Mook hero monsters. Each dungeon is aligned to a different enemy faction, being:
    • The Steps of Torment, an underground ruin filled with The Undead.
    • Port Valbury, a ruined city overrun by the Aetherials.
    • The Bastion of Chaos, a realm of the Void filled with Cthonian demons.
    • The Ancient Grove, a forest full of beasts corrupted by Aether and Void energies.
    • The Tomb of the Heretic, a ruined temple occupied by Eldritch and Celestial monsters.
  • Minecraft Dungeons:
    • There are secret dungeons that can be accessed after you find a scroll that unlocks them in their parent dungeon. There are 5 of these in the base game, with each Island Realm DLC having only one, which are always found in their first mission. The Nether and End DLCs do not have these as the former has their scrolls placed out in the open on the main path (though they're still labelled as secret missions) while the latter doesn't have any secret missions.
    • The Secret Cow Level, being a reference to the one in Diablo II, can be unlocked after completing the game on Default difficulty and collecting a rune that is hidden in every main mission in the base game.
    • A few updates to the game have added a couple Island Realms missions to the game for free, namely Treetop Tangle and Gauntlet of Gales. These missions last as long as a normal level, with the former having its own boss and items associated with it, but are not part of the game's story.

    Platform Games 
  • Castlevania has had several Bonus Dungeons over the course of the series.
    • The Towers of Eternity and Evermore in Castlevania: Curse of Darkness - both are fifty floors and feature large amounts of combat, and the latter can only be accessed from the former.
    • The Nest of Evil in Castlevania: Portrait of Ruin. Could only be accessed after exploring 888% (Yes, 888%) of the castle. Mostly just previously fought enemies, with bosses ripped right out of previous games. No real story, though getting to the bottom will net you the most powerful double-team spell in the game.
    • The Battle Arena in Castlevania: Circle of the Moon. Very challenging in that your Magic Meter is drained while inside. (Though a trick can let you cast one spell if you're quick) You can bail out if it proves too tough, but you have to play it completely through in order to get one of the most powerful suits of armour in the game.
    • The Forbidden Area in Castlevania: Aria of Sorrow. It's home to a somewhat good weapon, a powerful piece of armor, and the Claimh Solais, which on top of having a very high Attack stat is remarkably long and swings in an arc, attacking enemies above and ahead.
    • The Floating Catacombs in Castlevania: Symphony of the Night. It's home to Galamoth, the most powerful boss in the game; defeating him nets you the Gas Cloud relic, which makes your mist form harm enemies. The Floating Catacombs are completely optional, since there are no Vlad relics up there.
    • In a way, the Stage 5' in Castlevania: Rondo of Blood/Dracula X Chronicles. Accessing it in Rondo requires that you beat the game, and accessing it in DXC requires that you defeat Death, the boss of Stage 5. Until you do so, if you try to get a blue orb (which takes you to lower-path stages) in Stage 4 or 4', Death will change it to red. Oh, and if you think the rest of the game is hard, Stage 5' kicks the difficulty up a few notches.
    • The Training Hall and the Large Cavern in Castlevania: Order of Ecclesia. While the latter is a Monster Arena, the former is strictly a platforming challenge.
  • Copy Kitty features World 13, a bonus set of levels exclusive to Boki's campaign, featuring unique hell and heaven-based enemies in environments that sharply contrast the rest of the game. The Normal version has blood, bones, and a darker color palette with an Eldritch Abomination at the end of a difficult series of levels with downright bizarre powers to copy. On Hard Mode, after completing a lengthy checklist of achievments, the levels feature holy-themed enemies with more unique abilities and a truly spectacular Superboss.
  • Distorted Travesty has a number of unusually difficult bonus areas that open up along the way. However, the big one is the Spire of Forgotten Souls, a 100 floor Timed Missionnote  filled with some of the most devilish Platform Hell that the creator could come up with. The Superboss lurks at Floor 100, as well.
  • Donkey Kong Country:
    • Donkey Kong Country 2: Diddy's Kong Quest and Dixie Kong's Double Trouble! both have Lost Worlds that you need bonus coins to enter, and these coins are hidden in the regular levels.
    • Donkey Kong Country Returns: The Golden Temple, which is only accessible after completing the game and clearing all Temple levels in the regular worlds. It only has one level in the Wii version, but it has nine in the 3DS one; all of them are very challenging, and require good reflexes and timing to be conquered.
    • Donkey Kong Country: Tropical Freeze: The Secret Seclusion, which requires gathering the relics located in the Temple levels (themselves Brutal Bonus Levels) to enter, and can only be unveiled after defeating the Final Boss and clearing the game once. It consists of three exceptionally challenging levels, and completing them unlocks Hard Mode.
  • Eversion has Stage 8 and Layer 8, which is unlocked by getting all the gems before finishing Stage 7.
  • Hollow Knight has the Hive, which has little if any relevance to the story, lacks a local map of its own despite being considered a distinct region on the world map, is only necessary for obtaining a Mask Shard, two Grubs, and the Hiveblood Charm in a completionist run, and the entrance can be tricky to find if you don't use spells.
  • Every game in the Klonoa series includes one or more "EX Visions" available after completing the main plot. These are usually much harder than anything else in the game.
  • Ori and the Blind Forest: Definitive Edition features the Black Root Burrows and its Lost Grove sub-level, which reveal the backstory of Ori's adoptive mother Naru, and grant Ori two new Ancestral Tree skills, which are also required to access new secrets in the main game for 100% Completion.
  • Super Mario Bros.:
    • The series's Ur-Example is Worlds 9 through D in Super Mario Bros.: The Lost Levels. They're unlocked after completing the first eight worlds without using cross-world warp pipes (in the NES version, the game has to be completed eight times, but in All-Stars only once will suffice).
    • Star Road and Special World in Super Mario World. The first world is accessed at five different places in the main seven worlds; the second is unlocked via the secret exit in the final level of Star Road (for which it's required to have all colored blocks activated in the game).
    • The New Super Mario Bros. games have one of these in each game unlocked by beating the game, starting with New Super Mario Bros. Wii. That one is based off of Special World from World, New Super Mario Bros. 2's is simple, and New Super Mario Bros. U has it based off of Star Road from World. Like Star Road, there is once again something unlockable in the middle, though it is only one level instead of a whole world this time.
    • The Trial Galaxies in Super Mario Galaxy are unlocked by finding all three Green Stars. The galaxies in the Garden, meanwhile, are unlocked when all Grand Stars minus that of the final level are collected.
    • Super Mario Galaxy 2 has the Grandmaster Galaxy after completing everything else, found in World S (itself a post-finale Bonus Stage).
    • Super Mario 3D Land outshines all of the previous Mario games in this regard, and to date all subsequent ones: Eight full special worlds, each one a counterpart to one of the standard worlds full of Remixed Levels. Special 8 has a Brutal Bonus Level on its own, likely a nod to Super Mario Galaxy 2. Its sequel, Super Mario 3D World, has only four such worlds, but the difficulty and complexity of the levels is intact; the last world has only three levels, but they're by far the most formidable in the game.
  • Wonderboy III The Dragons Trap's 2017 remake adds six hidden "Unknown" areas, one for each of the player character's forms (the last is only available in the Playable Epilogue after regaining your Hu-Man form). Completing these rewards the player with Charm Stones, which boost your Charisma to allow you to purchase the Infinity + 1 Equipment.

    Puzzle Game 
  • Roll Away has The Final, 20 levels much larger and more complex than in the main game and you can only save at the half-way mark.

    Role-Playing Games 
  • Mull's Dungeon in Atelier Iris is only accessible after beating the game and contains a Superboss stronger than the final boss.
  • Atelier Sophie: The Alchemist of the Mysterious Book: After beating the final boss, you can download the additional map "Hidden Archive," which contains higher quality materials to gather, and tougher enemies to guard them. (Tormented Beast says hello!).
  • Avantasia: The Game has Via Inocencia, which is accessible only if you refuse to help any snakes during the main game.
  • Baldur's Gate:
    • In the first game, both the Ulcaster Ruins and Firewine Bridge are also completely optional. They are nowhere near as complex or deadly as Durlag's Tower though.
    • Baldur's Gate: Tales of the Sword Coast contains Durlag's Tower, a looming castle crammed full of thoroughly unpleasant enemies - and very large traps.
    • Baldur's Gate II: Throne of Bhaal has Watcher's Keep, a five-story dungeon (plus one extra for the boss fight) featuring some of the most complex puzzles and challenging fights in the game, eventually climaxing in a fight with Demogorgon, who is not only, as a good Superboss should be, the most poweful enemy in the game, but the most powerful being in the entire setting!
  • A 100 floor dungeon exists in Beyond Oasis. There are prizes every 10 levels, and if you can make it all the way to the bottom without having to turn back to restock on supplies, your ultimate prize is an indestructiblenote  Omega Sword.
  • Blue Dragon has the downloadable Shuffle Dungeon, which gives you several new items to collect and some new monsters to fight.
  • BoxxyQuest: The Gathering Storm has two - the Deep Web and the Sky Abyss. The first is a long, confusing, and terrifying labyrinth that can be accessed by gathering a set of keys held by seven specific NPCs. The second is unlocked in the epilogue by completing all of the Inbox missions, and leads to the game’s Golden Ending.
  • The Updated Re-release of Chrono Trigger adds Dimensional Vortexes unlocked after the final boss, as well as the Lost Sanctum. Even the original SNES version of the game has the Black Omen, an optional dungeon (although necessary to access New Game Plus) that can, through the magic of Time Travel, be cleared three times for maximum loot.
  • Chapter 8 in Dark Chronicle, which comes after defeating the main villain. Long story short, you go through an extra dungeon and end up fighting a hidden boss.
  • The Cow Level in Diablo II (and the Hellfire Expansion Pack for Diablo (1997)), inserted as a response to a rumor from the original Diablo that such a place existed. Later, the 1.11 patch introduced an elaborate Pandemonium quest with several bonus dungeons.
  • .hack gives us the Bonus Dungeons after the end of every game. In G.U.'' one of those is called the Forest of Pain. How utterly appropriate.
  • Some Dragon Quest games have added bonus opportunities as well, in each main series game starting with V and each remake starting with III.
    • Dragon Quest VI allowed you to defeat the equivalent of Satan, upon which he beats up the normal final boss for you.
    • Dragon Quest VII features a Bonus Dungeon where you fight God. Literally. A second bonus dungeon features an easier bonus battle with the four elemental spirits seen earlier in the game, after which you get the chance to invite God to live in your immigrant town.
    • Dragon Quest VIII's Bonus Dungeon gives us the Hero's backstory, and a boss with several progressively different forms requiring different tactics to defeat- and his final form is styled to resemble the final boss from the original Dragon Quest, especially during his "psyche up" pose.
    • The PSX/DS remake of Dragon Quest IV includes a bonus dungeon which expands on the story, even allowing you to redeem the (apparent) Big Bad, and the former final boss!
    • The SNES/SFC remake of Dragon Quest III includes a new bonus dungeon which also adds a small piece to the story, enabling the hero to revive his dead father as a wish granted by a Shenlong-like dragon... and part of the bonus dungeon itself is a sky castle the game calls "Zenithia" according to translations, suggesting a connection to Dragon Quest IV. The GBC version takes it a step further with an additional, story-less dungeon and boss to fight after that one... if the player can collect every single randomly-dropped Monster Medal in the game.
    • Dragon Quest V: Estark's Labyrinth is unlocked after beating the main game. Estark, one of main enemies of Dragon Quest IV, lies at the end, with the difficulty significantly ramped up. Beating him unlocks the last T'n'T board and beating that nets you the last two recruitable mons, who at this point are just for bragging rights. The real challenge is beating the Superboss in under fifteen rounds, which earns the final Knick Knack for your museum. Estark's Labyrinth was the first postgame bonus dungeon in the series.
    • Dragon Quest IX has a series of bonus story events, bosses, a few Bonus Dungeon areas (and several more randomly generated ones), and other content that can only be accessed after the main game "ends", including battling (and leveling up!) the final bosses (and a few less-than-final bosses) from the previous 8 games, but it really blurs the line since over half the playtime can be spent on postgame bonus content.
  • The Chicken Level in Dungeon Siege. Hidden behind a series of riddles and item-gathering quests, this was populated with... well, killer chickens with an extraordinary number of hit points. The level was filled with large amounts of fabulous treasure and hard-to-find items for anyone brave and strong enough to defeat the fowl beasts (pun intended).
  • Eiyuu Senki: The World Conquest has Shambhala on its True End route and is considered the final challenge of the game due to it being 10 battles in a row of increasing difficulty and characters used in one battle cannot join any of the others.
  • Elden Ring has plenty of these:
    • The Consecrated Snowfield is a fairly hidden away very late game area, teeming with very strong late game enemies like the Albinauric archers. Half of the area is also covered in a blizzard, obscuring vision and hiding these enemies. This area also gives access to the Mohgwyn Palace and to Miquella’s Haligtree. This area is only accessible by collecting two medallions - one in Liurnia in a fairly hidden away village, and the other far later into the game in a tough as nails castle with an even tougher boss at the end.
    • The Mohgywn Palace is fairly small but absolutely full of tough enemies that abuse blood loss, a very strong mechanic that shreds through your health when fully built up, and one of the game’s hardest bosses, the Lord of Blood Mohg. Guess what he also abuses. This area can only be accessed through progressing through Varré’s quest line, or through finding a rather obscure portal in the Consecrated Snowfield. There is a small saving grace, however, in that Mohg is cripplingly weak to blood loss himself, so you if you are specced out to inflict it as quickly and as often as possible (and given how powerful it is, chances are high you will be), he'll probably die even quicker than you.
    • Miquella’s Haligtree probably fits this trope best. Only accessible through solving a puzzle in the aforementioned Consecrated Snowfield, and you’ll have to deal some nasty Black Knife Assassins and Albinauric Archers to do this. Once you’re there, you’ll be met with a rather beautiful town in a tree. That’s absolutely full of the toughest enemies Elden Ring has to offer. Much of the level takes place on tree branches where you have a very high chance of simply falling off. With enemies that can push you easily off from range in the form of Oracle Envoys. And even when you’re on safer ground, it’s hardly safe. Be prepared to deal with all different kinds of knights, battle mages, soldiers everywhere, early game bosses now as standard mobs, Kindred of Rot that now hit like a truck with their Pest Threads, bosses roaming around like Erdtree Avatars, pools of Scarlet Rot that you can’t run through, and (most sadistically) an Ulcerated Tree Spirit fought on a tiny platform to be able to finish Millicent’s questline. One (thankfully optional, but that hides very good items) section of the dungeons even has five of the infamous revenants in one passageway!! The end boss of the dungeon? None other than the hardest boss in all of Elden Ring, and arguably in ALL FROMSOFT GAMES, Malenia, complete with two phases, scarlet rot attacks, lightning speed, hovering attacks, lifesteal.. and Waterfowl Dance, a move that oneshots players without very high levels in HP and heavy strong armour, greatshields or some other way to dodge the attack like Bloodhound Step.
  • Epic Battle Fantasy series:
    • Epic Battle Fantasy 3 has special rooms accessed by having enough achievements. The one at Volcano Peak contains enemies stronger than the final boss.
    • Epic Battle Fantasy 5 has several bonus areas, many exclusive to the Steam version.
      • The Freezeflame Dungeon, Mineshaft Maze, Deathly Hallows, and Crystal Caverns are caves smaller than the main dungeons proper. Each of them has a stronger counterpart to a main story boss fought at the end, with the Crystal Caverns having an extra boss on top of that.
      • Version 2 updated Greenwood Library to have a short dungeon with unique enemies, culminating in a Boss Bonanza against four living sketches.
      • The Great Sea in Version 2 has both a Nostalgia Level and an area where the team is restricted to one party member.
      • All versions of the game have five Glitch Areas making up one sidequest, and three small basement dungeons and the Forgotten Temple making up another.
      • The Temple of Trials is the game's Brutal Bonus Level, intended to be the hardest of the optional areas.
  • Etrian Odyssey series has one Bonus Dungeon in each of the games, accessible only after you beat the Final Boss. And each dungeon have a True Final Boss also.
    • Etrian Odyssey: Claret Hollows. A stratum with suspiciously organic features located within the deepest insides of the Yggdrasil Labyrinth, even below the ruins of Lost Shinjuku. It has a brutal combination of hazards (such as teleporters that make navigation difficult and toxic puddles that are harmful upon contact) and powerful enemies, and hosts the Primevil (Yggdrasil Core) at the very end.
    • Etrian Odyssey II: Heroes of Lagaard: Forbidden Wood is a lush, seemingly-paradisial forest located far above the highest floors of Heavenly Keep. It's filled to the brim with dangerous monsters, and navigating across is is a big challenge on its own due to the high number of harmful ground areas, disorienting teleporters, and fog that reduces visibility. The boss is Ur Child, the ultimate creation of the Overlord and one of the strongest living beings in existence.
    • Etrian Odyssey III: The Drowned City: The Cyclopean Haunt is an eerie, seemingly-organic stratum whose walls appear to be made of flesh and tentacles, and features all sorts of vicious monsters and hazards (such as slippery slime that makes navigation difficult due to acting like Frictionless Ice, floor tiles that break upon being stepped on and take characters to a lower floor, and parts of the map that cannot be drawn or marked in any way). It is watched over by the almighty Abyssal God.
    • Etrian Odyssey IV: Legends of the Titan: The Hall of Darkness is an Abandoned Laboratory where Imperials used to work on a living failsafe should the Yggdrasil reach terminal corruption, only for that failsafe to end up killing everybody within and turn the whole place into a ghost building where all walls are stained in blood. In addition to hosting exceptionally strong enemies, it also has Wrap Around corridors, toxic puddles, a huge warp maze, ice walls and ice floors that can be melted and later restored (which has to be done from time to time for a successful navigation), a room with a strong stench of miasma, and in the end the aforementioned failsafe: The Insatiable Pupa (which can grow to become the Warped Savior).
    • Etrian Odyssey V: Beyond the Myth: The Empyreal Bridge is an otherworldly labyrinth that goes well beyond not only Yggdrasil, but also the atmosphere of the planet, thus being a Space Zone. Deceased planets can be seen from afar, and the stratum is home to vicious extraterrestrial creatures as well as hazards like toxic puddles, color-coded teleporters, and a layout and design that violates many laws of physics. Awaiting at the end is the Star Devourer, which is currently sealed and left in that state unless the player's characters wish to unseal it and start the battle of their lives...
    • Etrian Odyssey Nexus: The Abyssal Shrine (not the same one from Etrian Odyssey III) has a layout and architecture reminiscent of the cardinal Shrines built all over Lemuria, and to a lesser extent the shrine built inside Yggdrasil Labyrinth, but the similarities end there. It features the most sordid fights against enemies (and have a much higher frequency rate than the Random Encounters from all previous strata), as well as mind-bending Block Puzzles that have to be solved for a successful navigation. It is here where the once-peaceful Abyssal Princess lies.
  • Fallen London has the Cave of the Nadir which requires a lengthy process to unlock: you need to first complete two opportunity card-based stories, then do a time-consuming expedition to find the Cave's entrance with a rare item that drains your attributes if you hold on to it for too long, and finally pay a huge amount of money or find five of the aforementioned Artifact of Doom to actually open the Cave. After all that, your reward is the ability to explore a place that gives you opportunities to acquire valuable, hard-to-get items but erodes your attributes the longer you stay in there with a description of your skull bones trying to grow over your eyes if you stay too long. Essentially, it trades the typical "slay extremely tough opponents!" bonus dungeon set-up for a "get valuable items dirt-cheap...if you're willing to weaken yourself!" set-up.
  • The Fallout: New Vegas DLC Lonesome Road adds the Long 15 and Dry Wells maps, which are unlocked by launching nuclear missiles at NCR and Legion territory, respectively.
    • Also, the Courier's Mile, an irradiated crater created by the missile launched from Ashton that is home to Irradiated Deathclaws and Irradiated Marked Men, the latter of which regenerate HP from the radiation, as well as two of the warheads required for the Warhead Hunter achievement.
    • The main game has Deathclaw Promontory, home to the highest concentration of deathclaws in the game, as well as a suit of T-51b armor, a Multiplas rifle, and a tri-beam laser rifle. Also in the promontory is a suit of Enclave armor lacking a helmet, the latter of which can be found in Silverpeak Mine, guarded by the Legendary Cazador
    • There's also Dead Wind Cavern, at the end of which is another Superboss, the Legendary Deathclaw, guarding the unique grenade machine gun named Mercy.
    • Some of the optional non-story dungeons in Fallout 3 may count, such as Deathclaw Sanctuary, the National Guard Depot, Fort Bannister, which also houses a Superboss, and the Dunwich Building.
  • Very common with Final Fantasy games, especially in Updated Rereleases and remakes.
    • The Gameboy Advance version of Final Fantasy added four unlockable dungeons containing bosses from the 3rd to 6th games in the series. The PSP and iOS versions kept those and added a new dungeon on top of that, called the Labyrinth of Time.
    • Final Fantasy II added the Soul of Rebirth quest for the GBA and the Arcane Labyrinth and Arcane Sanctuary for the PSP/iOS.
    • Final Fantasy III has one of these ATTACHED to the Very Definitely Final Dungeon, with a TON of Superbosses, each guarding a specific class' Infinity +1 Sword. Though it is mostly easier than the rest of the dungeon, and the game itself recommends to tackle it. There also several others throughout the game like the Sunken Cave and Bahamut's cave. The 3D remake also adds an optional "???" dungeon, in which the all-new superboss is fought.
    • Final Fantasy IV Advance added two new dungeons, one on Mt. Ordeals, containing new equipment due to the fact this version added the ability to switch party members, and the Lunar Ruins, which contains character specific trials. The DS version removed both dungeons along with the option of party customisation. The Complete Collection for PSP, being based off the GBA version, restored all of it.
    • Final Fantasy IV: The After Years has one at the end of each character's individual chapter, usually given by the Moon Rabbit Challengingway. Golbez gets two.
    • The Sealed Temple in Final Fantasy V Advance. There are a ton of these in the original game as well, such as the water tower in Worus Castle (which gave you the Shiva summon), the basement of Castle Bal (for the Odin summon) and several others. Technically, everything after the Pyramid is optional, as you can go straight to the Very Definitely Final Dungeon as soon as you reclaim the Global Airship in the third world.
    • Fanatics' Tower in Final Fantasy VI, as well as Ebot's Rock, the Ancient Castle, and many others, all available during the second half of the game. Also the Dragon's Den in Final Fantasy VI Advance, which is much more hardcore than any of those, and has a MUCH harder Superboss. The Soul Shrine, also added in the GBA version, is something of a boss rush mode.
    • Shinra Mansion, the Sunken Gelnika and the Ancient Forest in Final Fantasy VII.
    • The Deep Sea Research Facility in Final Fantasy VIII.
    • The Omega Ruins in Final Fantasy X. Filled with some of the best loot and highest-XP enemies in the game, but also filled with brutal enemies, most notoriously Great Malboros (which have an 80% chance of opening with Bad Breath, which inflicts multiple status effects, and always get the jump on you unless someone in the party has First Strike on their weapon).
    • The Via Infinito in Final Fantasy X-2 was also 100 levels deep, and tied into the plot, having spirits of enemies (some who only died in cutscenes and not in fights with the main character) from Final Fantasy X corrupted into fiends as bosses every 20 levels, finishing off with undead Bare-Fisted Monk Trema.
    • Final Fantasy XII has a TON of these, most of them incorporated into areas explored earlier in the game, including: the side wing of Barheim Passage, the Garamsythe Waterway sluice gate waterways, the deeper portions of Lhusu Mines, the top half of the Great Crystal, the Subterra of the Pharos Lighthouse, and Phase 2 of the Henne Mines. Some are completely optional locations. In one case (Cerobi Steppe), the dungeon is not overly difficult, being accessible at your party's right level at the time and merely happens to be optional. The other three: Zertinan Caverns, Nabreus Deadlands, and Necrohol of Nabudis, are a different story. How bad are they? All of them are pretty innocuous-looking Beef Gates (the first in particular can be accessed a full 20 levels before you're supposed to), the second has a goddamn killer save/gate crystal, while the third's save crystal has, wait, what save crystal?
    • Lightning Returns: Final Fantasy XIII has the Ultimate Lair, only accessible if you've completed enough sidequests to unlock the 14th day. Each floor is inhabited by a different Last One, unless you've already driven the species to genocide, and a Superboss fight awaits on the final floor. The catch? The in-game clock continues ticking during battles, making the dungeon a Timed Mission.
    • Deep Dungeon in Final Fantasy Tactics.
    • Final Fantasy Tactics A2 has the Brightmoon Tor. There are three entrances, and each one has the player go through several consecutive battles before facing level 99 opponents on the top. The tor features monsters that only appear there, with insanely high speed stat and incredibly powerful abilities, such as the ability to cast Haste on all of their units, or reduce a target's HP and MP to < 10.
    • Beating every dungeon in Final Fantasy XV and clearing the game to unlock Chapter 15 reveals a sidequest called "Menace Beneath Lucis" in which the player is handed a key that unlocks the basement of eight of said dungeons. In every one of them, the player can take on a series of crowd battles against some of the game's toughest enemies and even a few variants that don't appear anywhere else in the game, and both completing the sidequest and obtaining each party member's strongest Infinity +1 Sword requires clearing every single one. Notably, the final one in Costlemark Tower (Which is considered a frustrating dungeon in its own right) ramps up the challenge by disabling healing items, and is widely considered the hardest mission in the game for that reason.
    • Final Fantasy XV also has an unusual variant in the Pitioss Ruins. It can only be accessed with the Regalia Type-F (which can only be modded to in Chapter 15), but it's not a combat area; it's a dungeon for puzzles and platforming. Due to a combination of such factors as XV's numerous combat Game Breakers, the gameplay being designed with combat in mind, an inability to use the main character's warping ability in a dungeon without combat, some less-than-intuitive puzzle solutions, and low lighting in a game where most of the main character's clothes are black, Pitioss Ruins are considered by some to be more difficult than the Menace dungeons.
      Ignis: Well, Noct? How did you fare?
      Noctis: Fare? Oh, there's nothing 'fair' about that place. I give up.
      Gladiolus: Well, winners never quit, and quitters never win.
  • Crossbone Isle of from Golden Sun. Not as difficult as a good deal of the examples listed already, but still can be a challenge. Golden Sun: The Lost Age has Treasure Isle, Yampi Desert Cave, Islet Cave, and Anemos Sanctum, all of which have their own superbosses (which do not necessarily have to be beaten before taking on the Anemos Sanctum, but you might as well since you have to progress at least part of the way through each to get the Djinn inside before you can unlock it).
  • Grandia:
    • The original Grandia also contained no less than three bonus dungeon; the Castle of Dreams, the Soldiers Grave, and the Tower of Temptation, with the former two being available only for a limited time, and the latter being available to near the end of the game but nigh impossible to actually find. All of them have significantly ramped-up enemy difficulty (but absolutely abysmal experience payout), and all of them contain some of the most useful equipment for that point of the game.
    • Grandia II has the Raul Hills labyrinth, which hide the best defensive/recovery mana egg in the game.
    • Grandia Xtreme's Vortex Corridor.
  • The "Another Goddess" quest in Half-Minute Hero, aside from being very long for the game's scope (most levels last about 30 seconds, while this one will take a good five minutes), harkens to another Marvelous Entertainment-created RPG: Valhalla Knights (the title even changes to reflect this). It's accessible during normal play, but because of the major change in style, the Time Goddess urges you to walk past it, on to the next quest. In order to actually play it, you have to defeat 108 bosses first. Harsh.
  • Jimmy and the Pulsating Mass has multiple optional dungeons, called Nightmare Zones, and as one may get from the name, they are strikingly different in tone compared to the rest of the game, featuring creepy environments and imagery, (usually) creepily looking enemies, and contain powerful creepy Optional Bosses in the end, who are much more difficult when compared to all other enemies faced prior.
    • The first accessible Nightmare Zone is located in the Wilted Lands, accessed by moving Punch Tanaka's pile of crashed motocycles using the Low-Level Goon form. It contains a creepy, claustrophobic environment that shifts to trap you inside and features creepy, hand-like rock formations. At the end lies Slither, an eyeless python who is even more difficult than the first boss.
    • The second Nightmare Zone is located within Fermata Forest, accessed by falling through the frozen lake by Ground Pounding it in the Grumble Bear form. Described as "a dream within a dream", it's a very open hollow frozen wasteland, themed after dreams and fears of never being able to wake up again, with Sleepwalkers, the resident enemies, resembling sleep paralysis demons. At the end lies a castle, where Jimmy can end up being trapped permanently unless he directly enters the staircase hallway when clocks are ticking, and once he does, he is greeted by Ebeezil, the Emperor of Dreams, who is said to destroy the world should he ever fall asleep.
    • The third Nightmare Zone is Turnbuckle's Mansion located in the Whispering Valley, accessed by growing a vine from the fertile patch in the Happy Little Sunflower form to climb up into the mansion. It is a huge Haunted House where the gameplay shifts into the Adventure Game-esque exploration and item hunt. As you progress further through the mansion, a Creepy Doll will appear to play a game of hide-and-seek, constantly jumpscaring you as you progress, and eventually, the Living Toys of the mansion will come to attack you unless you satisfy the aforementioned Creepy Doll. At the end of the mansion, Turnbuckle himself, one of Jimmy's long-forgotten toys, will appear to attack him.
    • Late in the game, the player can access a mountain at the Homeflower, where the formerly innocent crow used to fly around until it curled up in a ball, painfully undulating. The mountain features lots of acrophobic imagery, with the player constantly required to climb up, only to fall down on various collapsing bridges, with the enemies being zombified birds and bats, as well as Pud, a giant creepy cube-headed humanoid with Nightmare Face. On the top of the mountain, the player faces Grimclaw, the crow fully mutated by the Pulsating Mass into a monstrosity with the worms inhabiting its body.
    • After completing Cordelia Mouse's quest, the player will be informed by her family that she went missing. Under the Unbreakable Bridge, in the Mr. Cat's hideout, a closet will open, allowing the player to enter his dungeon, resembling a hollow gray mansion inhabited by hostile Living Shadows. Halfway through the dungeon, the player will end up in the fake version of Smile, and after passing through the place, the player will end up in the cavern full of creepy eyes. At the end of the dungeon, the player confronts Mr. Cat, revealed to be a shadowy feline monstrosity, and after defeating him, it's revealed that he murdered Coldelia Mouse in the cold blood.
    • Another Nightmare Zone is accessible in the Legato Castle by using 50's Style Vampire to enter the mirror in the castle's attic. It is told to serve as the prison to the former Queen of Legato and resembles the twisted form of Alice's Adventures in Wonderland, with the enemies being figures based on the playing cards (such as Jack of Clubs, Queen of Hearts, the Joker, etc.), the recurring NPCs being a caterpillar playing riddles with Jimmy and the disembodied White Rabbit heads set on pikes, and the gruesome imagery of flayed skin and torture instruments being seen late in the dungeon. At the end, Jimmy meets the Mad Queen, who turned herself into a huge skeletal monstrosity and desires to flay Jimmy alive under the belief that she will be able to "cure" him.
    • The second Nightmare Zone of the Legato Castle is accessible in Mr. Marvelous's home, by opening the middle toy box when Helga is not in the party. It resembles the castle hallways full of chests, most of whom are Mimics, and some either inflict negative effects on the player's next battle or increase the amount of money the player will get at the end of the dungeon. In the end, the player meets the Golden King, a golden Living Statue standing among the piles of treasure, which can be stolen during the battle. However, the more treasure the player will steal, the more dangerous the Golden King will become. After beating the Golden King, the player will get the amount of money depending on how much treasure they stole from the boss, with the amount increased by how many rubies the player has collected at the dungeon.
    • On Secret Meridian, behind the Legs of Ancient Giant, the player can access the Asymmetrical Cavern, a chaotic cave full of random patterns of numbers, with the music being the cacophony of voices yelling out random numbers interjecting with chaotic bass-line, and the enemies being the twisted geometrical figures or puzzles. The farther the player progresses, the more corrupted the cave will become, eventually resulting in the player being teleported at random, complete with the fakeout teleportation into the Path of Enlightenment, which is then followed by the reveal that they are still in the cave. At the end of the cave lie Imaginary Numbers, a bizarre, chaotic mess of symbols whose entire battle is a Luck-Based Mission due to its random nature.
    • In the cave under the Giant Garden, behind the cobweb that can be burned by the Rotting Jack O'Lantern form, the player can access another Nightmare Zone, themed around the darkness. The place is very dark, and the enemies here are various kinds of spiders, obscured by the darkness until they reveal themselves. At the end of the dungeon, the player faces the Whisper Weaver, a creepy Giant Spider with the Nightmare Face.
    • Once Jimmy has 100,000 dollars on his bank account, he can be invited for the luncheon for the Platinum Club members at the Accelerated Dynamics building. After leaving the luncheon room, he can enter the elevator, going to the higher floors of the building, only for the lights to flicker and the elevator releasing Jimmy in the office room, with the endless seas of cubicles. Despite being very mundane in appearance, with the enemies being the regular office people (along with killing machines), it still maintains the creepy feel based on the disturbing monotone office working conditions, with the background music consisting of nothing but office noises made into unsetting music track, the worker corpses hanging outside the windows, and one storage room with flickering lights occasionally flashing to replace the archive boxes with corpses and dismembered body parts. The boss of the location is Mr. Grouse, formerly a friendly banker turned into a Corrupt Corporate Executive willing to murder a child just to keep his arms dealing practices a secret.
    • Once Jimmy gets access to the spaceship, he can visit the Information Isle, home to the Information Guy. Or rather, the Information Guys, as he's not the individual, but the entire species, with the zombified remains of the Information Guys killed all over the course of the game infesting the isle. At the end of the dungeon, the player faces a totem that reanimates the Information Guys' corpses.
    • Once the player reunites all the missing monks of the Sacred Lantern, a Temple of the Inward-Looking Eye becomes accessible, and by using the 50's Style Vampire form on the mirror, the player can explore the rest of the temple. It is revealed to be the Temple of Doom, with several areas being flooded, and the temple being inhabited by the marine life and Lovecraftian creature-cultists desiring to bring the apocalypse. At the end, the player faces the Black Prophet, leader of the Apocalypse Cult using the Doomsday Clock to try to bring the end of the world, making him a Time-Limit Boss.
  • The Kingdom Hearts series, while known for its slew of hidden Superbosses, occasionally features some of these:
    • For any game featuring tournament cups in Olympus Coliseum, dungeon-like marathon battles are guaranteed. The Hades Cup of the first game, in particular, pits you on a very long stand against 39 waves of enemies before you fight Hades himself (who casually happens to be the only Disney villain in the game not be fought in the main storyline), and then another 9 waves to clear the tournament. II features matches in the Underworld that also have an end goal of facing Hades (who is now fought in the main story this time).
    • The Final Mix version of II has the series' first proper Bonus Dungeon, the Cavern of Remembrance, as it is the first full level designed to be optional content. Powerful recolored mooks populate the game's most difficult level that features the return of platforming elements of the first game, which are otherwise mostly phased out. The reward waiting at the end is a gauntlet of battles: data replicas of all thirteen members of the Organization, much stronger than they were before. Of course, you need to beat the game to unlock all of them but considering that you can't complete the Cavern without Sora's Final Form, which you only unlock after reaching the final level, that shouldn't make much of a difference.
    • The Mirage Arena of Birth by Sleep is essentially a replacement for the cups of Olympus Coliseum; it's completely optional and can be taken at (almost) any point in the game.
    • In Re:coded there are no classic tournaments despite Olympus Coliseum being present. Instead, it features a 30-floor labyrinth with turn-based RPG gameplay. Only 5 floors must be completed to advance the plot; the rest is optional. There are also hidden system sectors that only show up after you get your Scan ability to a high enough level, the last upgrade only becoming available after completing the story.
  • Kingdom of Loathing has the Sea, which unlocks after you beat the game's Big Bad, the Naughty Sorceress. It's full of tough monsters, exploring it initially requires you to wear an accessory that gives you a serious penalty to item drops and initiative, you can only take familiars that can breathe underwater with you, and unless you have a specific effect gained only by consuming certain items found in the Sea itself, it costs two adventures to explore a zone once. There's also the Clan Dungeons (Hobopolis, the Slime Tube, Dreadsylvania, and the Haunted Sorority House), which are intended for high-end players and full of tough monsters; and Fernswarthy's Basement, which is full of increasingly difficult challenges, but offers big stat bonuses every five levels, and powerful consumables that appear every 100 levels.
  • There's six of the things in Last Scenario, seven if you count the one that's really just a sequence of four bosses. Luckily, all of them give you some very nice rewards.
  • The Ancient Cave in the Lufia series has gone from 12 levels (Lufia & The Fortress of Doom), to 100 levels (Lufia II: Rise of the Sinistrals), to 200 (Lufia: The Legend Returns) throughout the various games on SNES and Gameboy.
  • The Mega Man Battle Network series is known for its expansive bonus dungeons, taking the form of huge mazes with doors that must be unlocked by completing some objective elsewhere in the game. BN2 had WWW Area, 3 had Secret Area, 4 had Murkland, 5 had Nebula Area, and 6 had the Graveyard, a Super Mode Boss Rush.
  • Might and Magic: World of Xeen:
    • After freeing Sandro, the Lich-ruler of Necropolis, you get the key to the game's bonus dungeon, the Dungeon of Death, which requires access to both Clouds of Xeen and Darkside of Xeen to enter. Upon entering the Dungeon of Death, expecting highly difficult end-game enemies... the level is instead completely devoid of any enemies at all. It is actually a giant Crossword Puzzle.
    • Played straight in the lower levels of Dungeon of Death, once the crossword puzzle has been solved. However, level 4, the final level, is very goofy, full of Xeen-Maker Machines, and the only actual reward for completing it is a silly and utterly pointless Easter egg.
  • Monster Girl Quest: Paradox has the Labyrinth of Chaos, available after clearing the main game. It has two different sections, the Trials of Chaos and the Labyrinth of Chaos (yes, it has the same name as the area as a whole). The Trials of Chaos are ten floors in length, with a boss on the tenth floor, and are further divided into eight types that each have a different theme, enemies and rewards (e.g. the Eternal Forest consists of forest maps, is inhabited by forest enemies and contains light armour). The Labyrinth of Chaos has an infinite number of floors, with a boss every ten floors and an optional superboss every hundred floors. Also, both the Trials and the Labyrinth have different gameplay from the main game: enemies are Pre-existing Encounters instead of Random Encounters, you gain Rare Points as you progress, you get more valuable treasures based on your number of Rare Points, and you can upgrade equipment by applying Gems to it or merging two pieces of equipment.
  • Monster Hunter Stories 2: Wings of Ruin has the Elder's Lair, a 9-floor dungeon unlocked after beating the main game. To advance through each floor you have to perform specific quests, such as breaking certain body parts on the monsters, or completing puzzle fights within a certain time limit. After completing that, you unlock the S. Elder's Lair, a repeat of the Elder's Lair but with MUCH tougher monsters. At the bottom of both lies the game's Superboss: the Fatalis, reprising its role from the first game.
  • In Muramasa: The Demon Blade, there are several dead end paths that serve this purpose. When you beat the game once with both characters, all boss dungeons are available, turning them into this. Finally, the enemy lairs are bonus dungeons, including the aptly named level 92 Enemy Lair "Total Pandemonium/Night of Absolute Chaos." You have to fight through multiple waves of almost every type of enemy in the game. This includes some of the bosses as well as clones of the player characters.
  • OMORI has the Recycultist's HQ. The difficulty mainly manifests in the dungeon operating under real life rules, drastically reducing chances to heal Heart and Juice.
  • The Server Room in Opoona. It opens up about midway through the game, but actually challenging it at such a point is not especially advisable. In addition to containing Mooks that are extremely fast, can heal themselves, and prevent you from using your Force (magic), the battle stages are full of bombs, which prevent you from using just about any hit-all abilities lest they explode. (And if they do so, they'll knock off about 100 HP—about three or four is enough for a Total Party Kill.) And if that doesn't kill you, the room is also home to Salamanders, one of the game's most brutal Boss in Mook Clothing monsters. However, you can leave at any time to save and heal without losing your progress.
  • Paper Mario:
    • Paper Mario: The Thousand-Year Door contains a bonus level called the Pit of 100 Trials, consisting of 100 floors populated by increasingly tough enemies. Every tenth floor is a rest floor with a new badge/item and a pipe you can use to leave, but you have to clear the lot in one go to reach Bonetail, the Superboss that lives at the bottom.
    • Super Paper Mario has not one but two Pits of 100 Trials, one for Flipside and one for Flopside. The former is reminiscent of that of the previous game, and home to Wracktail, an upgraded version of the first boss Fracktail. The Flopside Pit, on the other hand, is populated solely by "Dark" versions of the game's enemies that are far stronger than those found elsewhere. To make things even worse, you have to clear it twice before the final Superboss, Shadoo, will face you. Post-game you can also visit Sammer's Kingdom for the complete Duel of 100. One hundred battles in a row, with no interruptions like in the main story. You do get to save after every 25 fights, at least, unlike the Pit of 100 Trials.
  • Persona 2:
    • Innocent Sin:
      • The Abandoned Factory, where enemies from previous dungeons can be fought again. Different areas unlock depending on how far you're in the game, and several sidequests take place there, like the hunt for the legendary weapons.
      • The PSP remake adds the Climax Theater, which features warped versions of St. Hermilin High School and Karukozaka High School as dungeons.
    • Eternal Punishment has several.
      • The equivalent of the Abandoned Factory is Kasugayama High School and the bomb shelter underneath, which was a storyline dungeon in Innocent Sin.
      • Later in the game, the Giga Macho music store and Mu Continent (both of which were also storyline dungeons in IS) open up when you spread a rumor about rare demons lurking there.
      • Finally there is the he EX Dungeon, available via New Game Plus.
      • The PSP remake of the game adds Kadasu Mandala in the list, as part of Tatsuya's Scenario, but only if you take Nanjo's route.
  • Monad block in Persona 3. The game's ultimate boss can be fought on the final floor. Meanwhile, Persona 3 Portable has the Vision Quest, hosted by Margaret, from Persona 4 in the Desert Of Doors from FES. While not a dungeon in the same sense as Monad, it does feature superboss versions of all the Full Moon Shadows as well as hidden boss that some are claiming is harder than Elizabeth/Theodore. Yes, you get to fight Margaret. And she isn't going to cut you any slack.
  • Persona 4: This is played with in the Golden version; if you maxed out the Aeon Social Link before clearing Magatsu Inaba and then ask Margaret on January 2nd to look for Marie, you will unlock the Hollow Forest. While it's possible to fight the True Final Boss even without unlocking the dungeon, the player must clear it if it's unlocked and doing so is a prerequisite for the Golden Ending.
  • Phantasy Star IV had a couple of optional dungeons that contained some nice loot, and in one case a Continuity Nod to the previous installment.
  • Pirates of the Caribbean Online:
    • The Cave of Lost Souls on Raven's Cove. It's totally optional, there's no quests that require visiting it, but it contains the toughest Ghost enemies in the game, including Foulberto Smasho.
    • The remake, The Legend of Pirates Online, introduces Forsaken Shallows. It's below Isla Tormenta's Cursed Caverns, has five new bosses lying in wait, and holds the highest-level enemies in the game. It's also the only place where you can get certain Legendary Cursed Blades. However, any quests that require fighting Davy Jones' minions can also be attained in the aforementioned (and slightly easier) Cursed Caverns, meaning you never have to step inside here unless you're looking for the strongest swords in the game.
  • Pokémon:
    • The games have these, starting with Mewtwo's lair, the Cerulean Cave in Pokémon Red and Blue. They are inaccessible until after you've beaten the game, and at the end lies a powerful legendary Pokemon for the player to catch, making it both a Superboss and an Infinity +1 Sword. Generations II and III possess a different variant. After the bonus dungeon you encounter, rather than a high-level Pokémon, a trainer with six high-level Pokémon, often the highest in the game. In GSC, this is Red, the protagonist of the original games as well as the male choice of protagonist in their remakes, FireRed/LeafGreen, with a party including a level 80 Pikachu and 70+ versions of all three original starters, Snorlax... and Espeon, for some reason. HGSS replaces the Espeon with a Lapras. The whole match has continuous hail and all of their levels have been buffed up. Pikachu is level 88 now! In Emerald, it's Steven, the mandatory Final Boss of the first two games of that generation, now cranked up to 11 as a Superboss. He has a similar team to the previous game (which was bad enough), but now they're all around level 80 rather than 50-60. Both fights are bragging rights only and give no real reward (although they are in fact repeatable, making them among the best spots to grind high-level Pokémon).
    • The Battle Frontier in the various games are all single playernote  tournaments with various gimmicks, which also tend to be source of the better hold items, evolution trinkets, technical machines, etc. This means that if you are going for 100% Completion (or wish to be tournament viable) you will need to master these game modes.
    • Pokémon Mystery Dungeon has many:
      • Of particular note is Purity Forest from the original pair of games. You can only bring one Pokémon in, which is brought down to level one. Also, all your items and money not in storage are destroyed. Good luck.
      • Zero Isle in the second pair, which is divided up into four parts. Zero Isle North simply doesn't give you any EXP but has some strong foes, but South, East, and West drop you down to level one at the start, you can't bring items to Zero Isle South or West and can only bring 16 items to Zero Isle East, and Zero Isle West also limits you to just the one Pokemon!
      • Destiny Tower in Explorers of Sky, in which you can only enter with one Pokémon, which is dropped to level one, enter with no items or money, all IQ skills nullified, hidden traps remaining hidden (plus the horrifying Random Traps and Grudge Traps), and the inability to be rescued if you faint!
      • Zero Isle Center in Explorers of Sky. You can only bring 16 items, it doesn't give you any EXP, has some dangerous foes at Level 90-99, hidden traps remaining hidden, Random/Grudge Traps, and no rescuing. Have fun with that.
      • Path of No Return in Gates to Infinity is one of the few dungeons with the absent-for-most-of-the-game hunger system. It's also a 99-floor dungeon that only lets you take one party member and reduces them to level 5, and you can't take items or money or recruit anybody. There's also Slumbering Path, which at least lets you take up to 4 party members.
  • Several examples from the SaGa series:
    • SaGa 2: Hihou Densetsu (Final Fantasy Legend II in North America) has the aptly-named Nasty Dungeon with single-tile hallways that span multiple screens and lead to dead ends and monster encounters the party cannot run from. Naturally the strongest weapons and equipment in the game are found here.
    • The Netherworld, Auldburg, Trials of Elore, Jewel Beast's Lair, Purgatory, and Shadow Palace in Romancing Saga. You only need to visit one of the first 3 that are mentioned in order to progress the story, You can open up all three before starting the endquests, but after completing Auldburg or The Netherworld, you cannot access the Trials of Elore.
    • Romancing Saga 2 has several: the Ice/Snow/Sand Ruins as well as a hidden town which allowed an deeper explanation of the game's backstory.
  • In Save the Light, "Secret Hoozywhatzits" are used to unlock doors leading to bonus areas full of stronger enemies. When entering them for the first time, one of your party members warns you of the increased difficulty inside them, advising you to come back when you're stronger.
  • Shin Megami Tensei III: Nocturne has both the Labyrinth of Amala and the Bandou Shrine. Completing the labyrinth gives you a sixth ending (and Superboss), and the shrine gives you the chance to acquire the secret 25th Magatama.
  • Shiren the Wanderer has a bunch of extra dungeons you can take on after beating the main game, including the Kitchen God Dungeon (a special dungeon where you start with Bufu's Cleaver, a weapon that can turn enemies you kill with it into meat), the Cave Behind the Scroll (a possibly shorter dungeon where you start with a Trap Armband, which enables you to pick up and place traps and use them against enemies, as well as gain experience for killing them with traps), Fay's Final Puzzle (a 99-floor marathon where even herbs and scrolls that you find will be unidentified), the Tainted Path (another 99-floor dungeon, with very strong monsters and a boss at the end), the Ravine of the Dead (a 50-floor frolick with tougher monsters, fake stairs, and lots of Monster Houses), and the Ceremonial Cave (a 30-floor labyrinth with tough monsters and another boss). The first three of these dungeons don't allow you to bring any items or money, and you can't bring companions into Fay's Final Puzzle.
  • The Star Ocean games all have at least one Bonus Dungeon. The Seven Star Ruins in the first game, Cave of Trials in the second, as well as its Gaiden Game, and Maze of Tribulations in the third, which jacked up the pot by adding Sphere 211, a 100-level dungeon, and the Urssa Cave Temple, a more puzzle-oriented Bonus Dungeon. The fourth game brought back the Seven Star Ruins and added the Wandering Dungeon. Many of these dungeons share the same background music (slightly remixed). Star Ocean: Integrity and Faithlessness has a large post-game dungeon called Maze of Tribulations, full of many superbosses and ending with the game's superboss, Gabriel Celeste. Also, when you complete it, you can challenge it again at increased difficulty two more times. (If you want 100% Completion, you will have to do this, as the powered-up versions of Gabriel Celeste have their own entries in the enemy database.)
  • An early example in Sword of Vermilion. Unlike all other dungeons in the game, nobody ever asks you to visit, or even mentions the existence of the dungeon where the Death Sword is found.
  • Tales Series:
    • The Moria Gallery from Tales of Phantasia. The later remakes expanded it with even more floors.
    • The 60-floor bonus dungeon of Tales of Destiny is a remake of The Tower of Druaga. A 10-floor version of the tower is the bonus dungeon in Tales of the World: Narikiri Dungeon 3.
    • Completionists playing Tales of Eternia will need to conquer Nereid's labyrinth, which involves five of your characters (including a couple squishy magic users), fighting solo against powerful boss enemies, followed by a difficult battle with the True Big Bad.
    • Tales of Destiny 2: A basement door in Aquaveil somehow transforms the town into a portal leading into a 25-floor dungeon, with a miniboss every 5 floors or so until you hit Magnadeus.
    • Tales of Symphonia has the Forbidden Anamnesis, a Tome of Eldritch Lore originating from Niflheim found in Sybak's library. The objective is to dive into the book's underworld and purge the evil from it. Its sequel has two of them, one of which requires you to be on a second playthrough. Bonus doesn't begin to describe it. The Japan-only PS2-version increases the difficulty of the Forbidden Anamnesis further. It adds another five floors, and adds two additional bosses: first, against a souped-up Magnius, Forcystus, and Pronyma on floor 10, and against Mithos' first form (minus wings), Kratos and Yuan on the 20th floor. Did I mention that you can only use three party members as opposed to four for the Mithos/Kratos/Yuan battle? Have fun!
    • Tales of Vesperia's Memory Dungeon. The graphics are blurry, it's brown, and all the sound effects sound far away, like you're hearing them on a camcorder recording the actual video game. In here, you fight the party's memories, and with that, every enemy they've faced in the game. This makes for some weird situations, like Stone Wall White Mage vs. Brainwashed and Crazy White Mage and Grumpy Old Man vs. the other half of his Split Personality. Strangely, for a game whose characters lampshade many things such as Crack Pairings and Dude Looks Like a Lady, this wasn't remarked about at all. The PS3 Updated Re-release ups the ante with the Garden of Izayoi, an incredibly long dungeon with the gimmick of progressing through the floors by way of actual combat; once you defeat a group of enemies, paths on the battlefield open up for you to traverse to another battlefield with more enemies, and you make your way through several floors of mazes. There are plenty of new Superbosses, including a horrific "monster" called the Spiral Draco, the King of the Entelexeia, which appears to have taken the title of "most difficult boss in the Tales Series."
    • Tales of Xillia The dungeon interior uses a similar format like that of Tales of Vesperia, in which that the player will go through what seems to be areas they've been to.
    • Tales of Xillia 2 This dungeon requires a completion of the game (once), a special key item and a trip to the Spyrius Corporation building. The dungeon poses as a normal warehouse in Drellin, but traversing it is a whole different matter. You will be faced with a dark dungeon. With a shadow silhouette palette of the enemies. The bosses itself resemble Ludger's team ending with two hard battlers at the end.
    • Tales of Berseria has The Heavenly Steppes (also called the EX Dungeon), which can be unlocked by reloading a save made after defeating the final boss. It features 6 different levels, each one harder than the previous. The level starts with one of a few random layouts including unique monsters (unique to the level, not to the layout type). Next is a layout that mimics an area from earlier in the game, including more of that level's monsters, chests, and a mission to complete several battles in a certain amount of time before the door is opened so they can proceed to the boss. There are some great equipment and abilities to be unlocked here, but the final boss gets stronger with each level of the area, and you must defeat the boss again in order to take any grade/potentites you've acquired into New Game Plus.
  • Theia - The Crimson Eclipse: The Extremordeal is an optional dungeon that starts at around the same difficulty of the main story Final Boss and gets increasingly more difficult the further the player goes. The gimmick to this dungeon is that the player can recruit characters that shouldn't be in the party story-wise, but they need to bring specific party members to progress in certain sections, including the new characters. This place can be accessed by doing an endgame sidequest for Rock in the White Deer Guild, but it only unlocks on Normal and Hard mode.
  • Torchlight has the Shadow Vault, known in Fan Speak as the Infinite Dungeon. Torchlight II has a dozen or more, ranging from level 45-105 and accessible through maps purchased from a special merchant after beating the main game.
  • Uncommon Time has two. After visiting the titular Uncommon Time in the main story, other gates to the dimension will activate — once in the temple where Aubrey was hibernating, and after that, Arietta's grave. The former explores Aubrey's backstory, and the latter elaborates on Arietta's life during the time of the first World Tuning. Defeating the True Final Boss after clearing both will net you the Golden Ending.
  • Vagrant Story has a bonus dungeon called the Iron Maiden. While areas in the game has a map to show which path leads to where, the Iron Maiden map doesn't. There's minimal to no light in the Iron Maiden, and the enemies are much more menacing than usual, and that's saying something. The boss waiting at the end is the reason why this dungeon is called "Iron Maiden".
  • The Seraphic Gate in all three Valkyrie Profile games. Valkyrie Profile 2: Silmeria and Covenant scales up the difficulty every time you beat it, and all require them to be beaten at least 10 times to get the Infinity +1 Sword, the latter two being far harder due to reasons stated above.
  • Wasteland, the original Post-Apocalyptic RPG, had this in the form of Finster's Head. A one-man-solo "dungeon" (VR sim, actually) in a party-oriented game that comes right after what passes for the game's Wham Episode can catch you by surprise with its (entirely optional) Superboss that yields the largest XP boon in the whole game (DOUBLE that if you kill him in melee) and an inventive puzzle maze.
  • The Abyss in Wild ARMs, 3, and Alter Code F. It was smaller in the first game, but all later incarnations had it at 100 levels deep. It exists in 5 as well, along with three other Bonus Dungeons, but it's much smaller.
  • Pork City in The World Ends with You. You visit the first two floors as part of the main story, but the other 11 floors and the Superboss aren't unlocked until Another Day.
  • After beating the final boss in Digimon World, there is a Bonus Dungeon that has no set location. The entrance is in one of many dungeon entrances around the map. Inside this Bonus Dungeon are color swaps of generic enemies that are extra powerful and at the end is the final boss once again, only this time at the highest health physically possible.
  • Xenoblade Chronicles X has several optional caves and Ganglion outposts, but the most prominent two are the Ganglion Anthropolis and the Divine Roost.
    • The former is only available after starting the mission "Definian Downfall", which in turn requires the completion of a large amount of previous missions. It's rife with many powerful enemies whose level swing between 55 and 65, and is home to powerful opponents like Urdu (accompained by several Milsaadi followers), a Level 85 Ganglion Skell, Rexoskell and Blood Despair.
    • The latter is only accessible via flying skells and has three powerful tyrants and quite a few level 60+ enemies including Telethia the Endbringer, which is level 99 and the ultimate Superboss in the game.
  • A third of Xenosaga 2 is side-quests and another third Bonus Dungeons.
  • In Yakuza: Like a Dragon, after beating the game the Millenium Tower becomes the "Final Millennium Tower" filled with even stronger enemies and retreads of previous bosses, including the final boss. At the top is a member of the Amon Clan waiting to challenge your party. In New Game Plus it becomes the "True Final Millennium Tower", in which you effectively have to be at the level cap to even stand a chance.

    Shoot 'em Up 
  • After completing Aleste, select Continue Game from the title screen to be taken to Round 0, a Palette Swapped and compressed version of Round 1. It's a relatively easy level and serves as more of a reward than anything.
  • Touhou Project:
    • The series, unusually for Shoot 'Em Up games, has made a tradition out of this. Of all mainline games, only the first game (which isn't a shooter) and the third game (which is a versus shooter) don't have any Extra Stages. Typically, the Extra Stage is unlocked after you've beaten all stages of the normal game without using any Continues (on Normal difficulty or higher for earlier games, later games allow for any difficulties). Storyline-wise, after defeating the Final Boss of the current game and solving the incident, the heroines are once again faced with another, smaller incident that is related to the main incident. They then set off once again to meet the Superboss. Alice and Marisa's pretending the game is an RPG in Touhou Chireiden ~ Subterranean Animism leads to the page quote in that game's extra stage.
    • Touhou Youyoumu ~ Perfect Cherry Blossom went one step further by having two Bonus Dungeons. The second one, called "Phantasm Stage", is unlocked after beating the first Extra Stage, and capturing 50 different spellcards.
    • In Touhou Kaeidzuka ~ Phantasmagoria of Flower View, which is a versus shooter, the Extra Mode is unlocked after beating all characters' Story Modes. That being said, it's less of a Bonus Dungeon like in the other games, and more of Arrange Mode. In the Extra mode, you first unlock Komachi's story, and after beating that you unlock Eiki's story. Gameplay-wise, the match starts in a state allowing for far more aggressive play than in the standard story mode and you start with no extra lives (although you earn extends much faster). The AI opponent has a timer (which scales like the regular mode's timer), and they're invincible before the timer runs out, upon which they'll quickly suicide and let you win.

    Simulation Games 
  • While completing the regular mines in Stardew Valley isn't necessary either, reaching the bottom earns you the key to the Skull Cavern, a much harder version of the mines that is totally randomly generated (in contrast with the mines, where the monsters and drops are randomly generated, but each floor's layout stays the same) and has no bottom.

    Survival Horror 
  • Ib has one that's accessible near the end of the game if you've gotten a 'survival' ending on a previous playthrough. It doesn't have super-tough monsters, but it does have a ton of puzzles that ding your Life Meter every time you fail to solve them and you're given only one chance to refill your life meter for the bulk of your stay there.
  • The Suffering features a pseudo-bonus dungeon in Chapter 19. If you deviate from the path that the AI leads you on, you can find a cave with a few NPCs and a slew of overly powerful monsters. The reward? The final component to the super-secret Flamethrower weapon (which certain exploratory players will have discovered several chapters prior).

    Turn-Based Strategy 

    Wide Open Sandbox