History YMMV / BloonsTowerDefense

** Quad, Muddy Puddles, #OUCH, Bloody Puddles, and Ravine are known together as the "True Experts" because [[DifficultySpike they are a vast step-up in difficulty]] compared to the lesser expert maps such as Workshop, Flooded Valley, Dark Castle and Infernal. Geared is sometimes added to the list, as [[NonIndicativeDifficulty despite merely being Advanced]], it is ''much'' harder than the other advanced maps, and its difficulty in CHIMPS mode is comparable to the first four.

* FridgeHorror:
** Several maps have removable obstacles (such as the statues in Chutes or the skull in Streambed). Generally, you have to pay some money for some engineer or chinook helicopter to come and grab it/destroy it. On the already somewhat ominously named map Bloody Puddles however, the car is a SchmuckBait: if you try to remove it, the chinook fails and crashes, creating another obstacle that you can remove, along with the car, for real this time. As no monkey is seen going out, combined with the "Bloody" part of the name, it is implied that they might have died.
** Some fans saw lethal implications of when monkeys were sacrificed, such as to a sun temple or to Adora, as CharacterDeath is otherwise averted[[note]]when one doesn't count the Bloons being popped[[/note]] in a SugarBowl like the Bloons universe.

** In an attempt to stop people from [[TierInducedScrappy abusing Blade Maelstrom in races]], leading to them being banned in most of them, version 24.0 capped its pierce to 100 bloons per blade so that it could no longer pop infinite bloons. The cap was soon doubled after complaints of players [[GoneHorriblyRight struggling to beat rounds 63, 76, and 78 with the cap.]]

** Striker Jones went from a MemeticLoser and TierInducedScrappy to being one of the most popular CHIMPS heroes for Expert tracks. First, he gained a new leveling bonus that lets him and other explosive towers to pop explosive-resistant bloons 50% of the time, and allows explosives to hit black bloons and [=DDTs=] every shot at level 19. Then, his Concussive Shells were buffed to stun bloons many times longer than they originally did, making them much more usable against both the blimp-infested rounds in the late-game and normal bloon rushes earlier. Additionally, his level 20 Artillery Command ability also was buffed to double MOAB Mauler damage when it is activated. Combined with MOAB Mauler spam, Striker Jones became a mainstay in CHIMPS strategies, with very difficult maps like Quad and Bloody Puddles not immune to his wrath.

* FridgeHorror: Several maps have removable obstacles (such as the statues in Chutes or the skull in Streambed). Generally, you have to pay some money for some engineer or chinook helicopter to come and grab it/destroy it. On the already somewhat ominously named map Bloody Puddles however, the car is a SchmuckBait: if you try to remove it, the chinook fails and crashes, creating another obstacle that you can remove, along with the car, for real this time. As no monkey is seen going out, combined with the "Bloody" part of the name, it is implied that they might have died.

* TheWikiRule: [[https://bloons.fandom.com/wiki/Bloons_Wiki The Bloons Wiki]].

* ViewerPronunciationConfusion: Geraldo's name is explicitly pronounced in a Spanish-like fashion in-game. Though Ninja Kiwi has said that "jer-al-doh" is acceptable, the proper pronunciation still isn't very well-known among the player base.

** When the Beast Handler was first released in 36.0 the third tier and onwards for the top path had an attack speed cooldown that was far shorter than it was supposed to be making them incredibly strong for their prices. The 36.1 patch that was released about two days later fixed this issue by reducing the cooldown to its intended value.

** When the Beast Handler was first released in 36.0 the third tier and onwards for the top path had an attack speed cooldown that was far shorter than it was supposed to be making them incredibly strong for their prices. The 36.1 patch released about two days later fixed this issue by reducing the cooldown to it's intended valus.

** In stark contrast to ''[=BTD5=]'', where the Monkey Engineer's Sentries were quite effective, the path with them is considered to be the weakest one for the ''[=BTD6=]'' Engineer, due to not providing nearly as much utility as Cleansing Foam, Bloon Traps, or ''especially'' Overclock for its price. Sentry Champion in particular is weak for its cost of $37,800. It doesn't compare well to the Sun Avatar, and while it synergizes unusually well with towers that boost its attack speed, the nerf of Overclock was yet another blow to this tower's viability. Finally, its gimmick that turrets explode when timed out or sold is considered to be too unreliable to be of any use. Some of the top path's infamy began to subside in 23.0, when top path engineers' sentries are now affected by the Deconstruction crosspath upgrade, which allows them to do an extra point of damage to blimps and fortified bloons. While Sentry Champion is now considered viable, however, the previous upgrades were still disliked. Thankfully, another buff that allows the sentries to be upgraded to stun bloons made turned them into a better-liked DiscOneNuke.

** In stark contrast to ''[=BTD5=]'', where the Monkey Engineer's Sentries were quite effective, the path with them is considered to be the weakest one for the ''[=BTD6=]'' Engineer, due to not providing nearly as much utility as Cleansing Foam, Bloon Traps, or ''especially'' Overclock for its price. Sentry Champion in particular is weak for its cost of $37,800. It doesn't compare well to the Sun Avatar, and while it synergizes unusually well with towers that boost its attack speed, the nerf of Overclock was yet another blow to this tower's viability. Finally, its gimmick that turrets explode when timed out or sold is considered to be too unreliable to be of any use. Some of the top path's infamy began to subside in 23.0, when top path engineers' sentries are now affected by the Deconstruction crosspath upgrade, which allows them to do an extra point of damage to blimps and fortified bloons. While Sentry Champion is now considered viable, however, the previous upgrades are still disliked.

** 33.0's preview annoucement made public the controversial change to impose a 3-Paragon limit to promote creativity in choosing Paragons. After feedback from the community, this limit was changed to 4 Paragons while an additional Content Browser editor function that allows players to set higher limits or unrestricted in player made Content Browser games. This was followed by NK announcing that they would like to backpedal further by removing the limit entirely outside of bosses and Contested Territory.

** Comanche Commander in ''Bloons TD 6'''s popularity has been split between "okay with supports that can affect its Comanche entourage" and "avoid like the plague, Apache Prime is superior in every way". Part of the division is fueled by Comanche Defense, the stepping-stone tier 4 upgrade, being often reviled for its unreliability of the Comanche summons. Due to Comanche Defense's poor repuation, the Commander gets tarnished as well. Additionally, whenever a support buff was nerfed, both Commander and Defense (which relied on them for usefulness) were often hit four times as hard. On the other hand, a few buffs (like Gwendolin's Heat it up) still remain useful for assisting the summoned Comanches, and it has been consistently buffed over numerous patches to make it a viable option.

** The Dartling Gunner is an interesting case, as the divide stems on its fun factor rather than usefulness. Its unique aiming gimmick has its fans, as it gives the gunner theoretically infinite and controllable range, but the increased level of control can feel annoying to constantly track.

** In ''[=BTD6=]'', prior to patch 6.0, most players ended up using the combo of a top-path Alchemist buffing a bottom-path Super Monkey and a top-path Ninja. Even after the nerf that causes top-path alchemist buffs to expire after a specific amount of attacks and bottom-path Super Monkeys got nerfed as well, several towers attacked slow enough to still be extensively paired with top-path alchemists, such as top path ninjas (still being the most popular one by far), bottom path submarines, and top path wizards. And then come Update 17, the bottom path Super Monkey got Darkshift, which then proceeded to bring this strategy back a bit.

** Freeplay ventures in the fifth generation always used Temples of the Monkey God due to being heavily boosted by their sacrifices on top of their base power, allowing them to handle the gradually stronger blimps that Freeplay almost solely consists of. The Vengeful True Sun God ''Bloons TD 6'' is the go-to tower for freeplay attempts as well for the same reason, though with the introduction of Paragons they're no longer the de-facto best freeplay tower.

** Since the buff of the dumb sniper, the 0-2-5 Elite Defender became the most used tower in Deflation Mode, as it is just cheap enough to squeeze into the 20,000$ budget if discounted by a village which is then sold, has global map coverage and can pop anything. Version 28.0 finally shut down this strategy by taking away its ability to pop lead bloons.

** In ''[=BTD2=]'', it was the black bloons who fit in here-- they were the only bloons to be immune to Bomb Shooters, and since the strongest bloon was the rainbow bloon, Bomb Shooters were used a lot. The only option against a frozen black bloon were the upgraded boomerangs, which fired in a rather strange pattern. Later installments gave Bomb Shooters shrapnel to deal with black bloons.

** [[EliteMooks Ceramic Bloons]], introduced in ''[=BTD3=]''. They are deceptively fast and are protected by an outer shell which allows them to absorb 10 attacks before popping, meaning they can take significantly more punishment than your average bloon. What's worse is that they can NoSell glue, almost OneHitKill you if they get through, and contain two Rainbow Bloons, which are plenty annoying on their own. But the problem arises when the game decides to [[ZergRush spam them in huge droves...]]

** The DDT from Bloons Monkey City returns in [=BTD6=], and it's just as awful. While it's slightly slower than it was before, and "only" contains 4 Camo Regen Ceramics rather than 6, it's still fast as hell, and was given additional HP so that it now has ''twice'' the health of a MOAB. It's immune to explosives and piercing damage, and is ''camouflaged'' on top of that, forcing all towers to get through ''three levels of immunities'' to even hurt the thing, leaving few towers that can take down a DDT without a lot of external help. Combine their myriad of immunities with their blazing speed and significant HP, and a group of DDT's can easily spell the end of your game. And like the MOAB, they tend to come in groups (although they usually aren't spammed), and are usually spaced far apart to mitigate SplashDamageAbuse used on them.

** ''[=BTD6=]'' adds Fortified Bloons to the lineup of special bloon types. Fortification can be applied to Ceramics, Leads and MOAB-class bloons to give them double health, significantly boosting their survivability. Even if you can handle normal blimps, one fortified blimp could throw you for a curve, especially if it's given to some of the tougher ones like [=ZOMGs=], [=DDTs=], or heaven forbid the BAD. Worse still, as the only "trait" that can be applied to a blimp, if a MOAB-class bloon has fortification, then ''every bloon it spawns up to Ceramics will also be fortified, including any blimps.''

** In ''[=BTD6=]'', in late freeplay rounds the game replaces Ceramics with Super Ceramics. They're much, much tougher than regular Ceramics (60 HP vs regular ceramic's 10 HP), move just as fast, and are spammed in similarly large numbers. They're so tough that towers focusing on popping a lot of Bloons at once, like Ultra-Juggernaut or Glaive Lord, become way less effective at their job. Furthermore, as regular bloons, they can have Camo, Regen, or Fortified properties (the latter of which will double their already sturdy HP), with Super Ceramics in later waves often having ''all three''. On the bright side, all of their descendants will only spawn one child Bloon when popped, but at that point all Bloons below Ceramics are non-issues anyway.

** Certain crosspaths have now-memetic nicknames, such as "ANGERY sub" for the 3-2-0 submarine (since its window literally TurnsRed while in possession of this crosspath) and "Dumb Sniper" for a right-path sniper with a middle crosspath due to its poor layer damage and general inability to pop lead bloons. The name became TheArtifact, yet sticked, after the crosspath became viable, arguably even moreso than the 2-0-3+ sniper. In general, choosing the inferior crosspath for a tower is known as a "dumb crosspath".

** The Flying Fortress upgrade for the Monkey Ace has been dubbed the "Big Plane" due to its upgrade description memetically solely consisting of a single sentence calling the Flying Fortress a "BIG plane". It is also sometimes known as the "ISAB Plane" due to the youtuber ISAB using it as an avatar.

* {{Fanon}}: Fans often depict Ezili and Adora as sisters, because of their similar expressions and hairstyle. They also make a good SiblingYinYang team, as Ezili is a dark-themed magic user while Adora is a light-themed magic user. Both heroes also have three abilities, second of which having sacrificial themes, making them similar. However, this is purely fanon, and nothing in canon suggests the two are related in any way.

** There's [[BribingYourWayToVictory a premium upgrade]] in the games past ''[=BTD4=]'' called "Double Cash", which doubles how much money you begin with, and how much you get from the bloons. Already extremely powerful by itself, but there's also a premium upgrade called "Healthy Bananas", which allows Banana Farms to give you more lives. Buying both will give you enough money to buy a Banana Farm from the beginning, with a little extra to buy one more cheap tower. Once the farm gets a few upgrades, it becomes ridiculously easy to rack up staggering amounts of money and lives.

*** The top upgrade path, specifically the Berserker Brew and Stronger Stimulant upgrades. These gave a major boost to nearby towers' range, pierce, attack speed, and most importantly, added one point of damage to their attack. Taking into account how most towers in this game use [[DeathOfAThousandCuts fast but weak attacks]], this more than ''doubled'' the popping power of a few nearby towers, all for a very reasonable price. Patch 6.0 {{nerf}}ed this by making the buffs last for a set number of attacks before expiring, meaning that the fast-attacking towers this strategy was most effective with would rapidly burn through the charges unless you used the final upgrade of the path, Perma-Brew, which makes the buff permanent but is extremely expensive.

** When the Engineer was finally introduced in version 12.0 of ''[=BTD6=]'', its activated ability, Overclock, proved to be massively overpowered. For a duration, it doubles the attack speed of one tower. The thing is, the duration is an entire minute, while its cooldown is only 45 seconds. It's possible to permanently or almost permanently double another tower's attack speed with Overclock, including the already powerful Tier 5 towers. Add in the fact that an average Tier 5 towers costs $40,000, while Overclock costs less than $20,000. It's considered so strong expert players are [[https://www.reddit.com/r/btd6/comments/dq0xee/comprehensive_tier_list_for_chimps_by_path/ modifying the tier lists based on how good a tower's synergy with Overclock is]]. 21.0 {{Nerf}}ed it by making it buff towers for an amount of time based on their tier and not their price, making it less overpowering when used on T4 and T5 towers.

** Psi has infinite range, doesn't need line of sight, can passively hit camo, and if placed from your first round, gains the ability to hit lead and ceramic bloons quick enough to be effective when they first show up. Their level 3 ability is a stun with a large area of effect and long stun time, which pulses multiple times at high levels to hit more bloons. Though their relatively slow OneHitKill attack limits their ability to take on large waves of bloons at first, combining Psi with a free Dart Monkey can get you through a lot of the early game and free up your resources to develop your own setup. Later on, Psi's [[SmartBomb Psionic Scream]] attack can easily destroy huge hordes of bloons, especially since they gain the ability to target [=MOABs=] at level 14 and [=BFBs=] at level 16 — countering [[ThatOneLevel the notorious round 98]] in particular very well. Psi's base cost was later increased from $800 to $1000 so that you can't place them down from the get-go, but their late-game power is still exceptional, especially on higher map difficulties where they level up faster.
** Geraldo's wares make him so stupidly versatile that he's a borderline MasterOfAll. Early game? His Shooty Darts are very efficient, copy most of the buffs Geraldo gets, and even scale well late game, and Geraldo himself is a decent attacking tower who's very cheap and has an unusually high amount of pierce. Bloons getting through your defences? Use a tub of Amaz-o-Glue or Creepy Idol to slow them down, or use his placeable Road Spikes to take out any that make it past your other towers. Need mid-game power? He can give your towers camo detection, damage, or sharp damage pierce for several rounds for really cheap, Worn Hero's Cape turns your free Dart Monkey into a Super Monkey for less than 2/3 the cost, Gerry's Fire adds Dragon's Breath to a tower for even less, and once you get the KillerRabbit, that thing can pretty much solo the mid-game. Struggling with tower DPS? Blade Trap lets you Blade Maelstrom anywhere and Genie in a Bottle will absolutely demolish blimps, and they're even better late game (you get a ''Super Maelstrom'' for around $500). Want lots of cash? Invest in an early Rare Quincy Action Figure and sell them for a huge lump sum of cash mid or late game, buy some Banana Farms and power them up with Fertilizer, then get several cash-generating abilities and use his Rejuv Potion to make that money again for just $1000! The only thing that's preventing Geraldo from clearing CHIMPS by himself is that he has no way to pop leads on round 28, and even ''that'' was solved thanks to the Scrapyard map and its Crusher trap, which (with careful use of Geraldo's Creepy Idol and Glue) eliminated his only weakness and allowed him to perform the second-ever [=1TC=] after pre-nerf Sauda. Geraldo did get a nerf in the next major patch on some of his items' uptime and price, but Ninja Kiwi does state Geraldo is supposed to be a [[DifficultButAwesome rewarding hero for those who know the game mechanics well]], which is why he's so versatile.

*** The Mobile and Steam versions, instead of Hypersonic Juggernauts, have a bug where Juggernaut monkeys gain the rapid-fire darts of the Super Monkey; this is the only time when it's a good idea to get the pierce upgrades for a Juggernaut, because the darts can still do a lot more damage with 4 pierce than with 1.

** The Infinite Stacking glitch in version 11.0 of ''6''. The Carrier Flagship upgrade of the Buccaneer allows you to place two land-based towers on top of it. But because [[DepthPerplexion the game is a 2D game pretending to be 3D and height is not considered in a tower's position, the spots' positions are actually slightly north of the flagship's position instead of being on top of it]]. Even if a spot's actual position overlap with the track, an obstacle, or another tower, the flagship allows you to place towers there. The fun begins when you use this trait with the Support Chinook's ability to move towers. Place a Carrier Flagship just slightly below a track, move a tower to a spot provided by the flagship, then sell the flagship while the Chinook is still moving. Tada! Now you have a tower in the middle of the track. This process is repeatable. Build another flagship in the same place, move a tower, and sell the flagship, and now you have two towers in the same position. Repeat until you're satisfied. [[https://www.youtube.com/watch?v=J5AhiH8PdXs Here's a demonstration]].

* GrowingTheBeard: The first four games are relatively solid, but simple, tower defense classics. ''[=BTD5=]'', on the other hand, offered dramatic changes to the formula, including more complex tracks, a completely revamped tech tree, beloved towers like the Sniper and Ninja Monkeys, and has a massive amount of content. It's telling that ''[=BTD5=]'' is the point where the games branched out of their restrictive Macromedia Flash format, and into actual games being sold on storefronts like Steam and Consoles.

* HypeBacklash: Despite months of excitement for the Engineer's Paragon in the buildup to its release in 32.0, the Master Builder was panned once it finally arrived. It overspecializes in the first path's sentry-based mechanics at the cost of abandoning nearly ''every'' other aspect of the second and third paths apart from buffing itself a la Overclock at the start of every round and being able to pin MOAB-class bloons in place, essentially making it a Paragon-level Sentry Champion. In conjunction with how versatile (and expensive) Ultraboost and XXXL Trap are, it is generally seen as far from a worthwhile upgrade, and players were already clamoring for Ninja Kiwi to rework it mere days after its release. Ninja Kiwi addressed this saying Paragons aren't meant to be just 5/5/5+ tower and don't equally feature aspects from all three paths, but the generally uncreative result of the final product, with people saying it's more of a Dartling Gunner Paragon, they say they will consider adjustments.

** IMF Loan was disliked when it was released. The upgrade costed $12,000, for an ability that gives you $10000, which ''needs to be paid back'', taking a percentage of your income until it's fully repaid. It gave you zero net cash gain. Even if the ability was used right away, players were actually in a worse position that if they hadn't purchased the upgrade in the first place ($12000 available cash vs $10000 available cash with debt). It was fortunately made cheaper in a patch, but even then, people generally avoided the loan ability itself and bought the upgrade either for its expanded bank capacity or as a stepping stone to the much more profitable Monkey-nomics.

** After Striker Jones was buffed, Quincy gained notoriety as the weakest HeroUnit. His main issue is that he's completely outclassed in the game's later rounds required on Impoppable and CHIMPS runs, since he's not very effective against large amounts of blimps or super ceramics. He may become a strong attacker as he levels up, but [[CripplingOverspecialization attacking is all he focuses on]] with no buffing or support powers, so once he gets outclassed he can't provide much else. Later patches have, fortunately, [[BalanceBuff significantly buffed Quincy]], making him [[CrutchCharacter far more effective early-game]] while still being able to contribute later on with Storm of Arrows.

** In stark contrast to ''[=BTD5=]'', where the Monkey Engineer's Sentries were quite effective, the path with them is considered to be the weakest one for the ''[=BTD6=]'' Engineer, due to not providing nearly as much utility as Cleansing Foam, Bloon Traps, or ''especially'' Overclock for its price. Sentry Champion in particular is weak for its cost of $37,800. It doesn't compares well to the Sun Avatar, and while it synergizes unusually well with towers that boost its attack speed, the nerf of Overclock was yet another blow to this tower's viability. Finally, its gimmick that turrets explode when timed out or sold is considered to be too unreliable to be of any use. Some of the top path's infamy began to subside in 23.0, when top path engineers' sentries are now affected by the Deconstruction crosspath upgrade, which allows them to do an extra point of damage to blimps and fortified bloons. While Sentry Champion is now considered viable, however, the previous upgrades are still disliked.

** The MOAB Mauler in ''[=BTD6=]'' has been in both ends of the trope. Initially, it behaved exactly as in previous entries - firing missiles that dealt 10 extra damage to blimps, while everything else took the normal bomb damage. In a game with so many effective ways to deal heavy damage to blimps, the MOAB Mauler was quickly overshadowed... until Patch 12.0 gave MOAB Maulers extra damage against Ceramic Bloons. Alongside the buffs Striker Jones got, MOAB Maulers went from an outclassed option to being heavily spammable. It became so good, that it started to get progressive nerfs on pierce, cost and Ceramic damage, to the point that, in version 30.0, MOAB Maulers no longer deal extra damage to Ceramics, putting it almost completely back into square one, where the MOAB-popping specialist is once again ignored in favor of other options outside of a few strategies, and even being turned into a MemeticLoser.

** The Cave Monkey in Frozen Over. Some joked that he had to be freed so players could harness his powers, other joked he had to be frozen in to seal away his power, either way, he was considered powerful. [[spoiler:And as of Update 17, you ''can'' free him--and he can stun [=MOAB=] class Bloons up to a ZOMG!]]

*** Once Striker Jones freed himself from this status, the fans took to making fun of Quincy instead, for being rather outclassed as a hero, his eternal memetic feud against the [=DDTs=], and his voice clips. However, Quincy is now liked for his usefulness on CHIMPS mode.

** Australians as a whole also fall under this, as players occasionally joke about how the Australian flag costs 60% more than other countries' flags in the Trophy Store for no apparent reason.

* PlayAlongMeme: Camo Bloons can't be attacked by towers who can't detect them, despite being just as colorful as regular towers, just with camo patterns on. Players like to joke they really can't see pictures of Camo Bloons. This is usually followed by a variation of "wearing the red wristbands", since the upgrade that lets Dart Monkeys see Camo is depicted in-game as a pair of red wristbands.

** Glue Storm was widely considered the worst Tier 5 upgrade in the game. It doesn't give any powerup, and its ability was basically the same as the Tier 4 Glue Strike, but lasts longer. Version 8.0 of the game buffed it by making its glue have a weakening effect during the entire duration of the ability, making it capable of supporting other towers offensively.

** Quincy was the butt of jokes among the heroes because he lost his effectiveness pretty fast. Anything he could do, Obyn Greenfoot could do it better (and more). Version 10.0 buffed Quincy by reducing his price so that he can be purchased the first round in any game mode, finally letting him be the early game hero he's supposed to be. Version 11.0 buffed him further indirectly by increasing Obyn's price. Quincy is now considered a viable hero, to the point of arguably outclassing Obyn.

** The Engineer's turrets can make tower placement annoying, as you can't control where and when they appear. You can sell them to get rid of them, but it's still annoying. Obyn Greenfoot's totem in ''[=BTD6=]'' used to suffer from this issue too (where it was even worse in CHIMPS mode, since you're not able to sell them) until patch 5.0 changed them to spawn directly on the track. The Engineer in ''[=BTD6=]'' thankfully averts this, as the Sentries they spawn have no footprint, and you can build towers directly on top of them.
** The inability for temple insta-monkeys to accept sacrifices has led to many players groaning upon receiving them, since much of a temple's damage comes from the sacrifices. Hence, preventing them from sacrificing towers is viewed as an undesirable gimp.

*** If you're feeling particularily masochistic, ''[=BTD6=]''[='=]s answer to NAPSFRILLS is CHAMPIONS, in which, in addition to the regular CHIMPS mode, you have to play in '''A'''lternate bloon rounds with no '''O'''p towers (all tier 5) and no '''N'''arcissists (heroes). Good luck.

** Variants of the [=2MPC=][[note]]On CHIMPS, have a tower score 2 million pops (out of approximately 2,045,000).[[/note]] achievement include the All Pops Challenge, where only one tower is allowed to pop anything, and the 2.6MP-ABR, where a tower must achieve 2.6 million pops in an Alternate Bloon Rounds game under CHIMPS rules.

* {{Shipping}}: The sixth game introduced heroes, which unlike the generic towers, have distinct characters and personalities. Naturally, fans began shipping them with each other. That said, since the game has a near nonexistent story, all ships count as ShipsThatPassInTheNight. The closest two heroes ever speak to each other is in Co-op mode, and even then they don't interact with each other nor behave differently than in the single player modes.

** Steeley, an achievement on the Steam and mobile version of ''[=BTD5=]'', requires you to pop 250,000 Lead bloons - but there are no bloons that contain Lead bloons, so Leads are much rarer than any other bloon. With only 277 Leads appearing in an 85 round game, you could play a map on Hard mode over 900 times and still not have enough to get the achievement. The only easy way is relying on Random Missions or the Wizard Lord mission. The latter method can be done with the aforementioned Regrowth Farming trick, not only by popping '''tons''' more leads than by playing normal maps, but also by ''raking in the cash'' because the regen farming patch in the Flash version doesn't apply here. Just make sure to get a [[WaveMotionGun Ray of Doom]] quickly to minimize lag compared to the defense you start the farm with.
** Sapper in ''[=BTD6=]'', which requires popping a whopping ''five million'' Fortified or MOAB class Bloons. Unless you're willing to go for extremely high freeplay rounds, it will take over a thousand 100-round games to reach that number. Even worse, upgrades that remove Fortified status, such as the Mortar's Shattering Shells, don't count towards this achievement. It's often one of the last achievements obtained for players and by far the hardest achievement that gives a MK point to obtain.
** Super BAD, also in ''[=BTD6=]'', requires you to pop 1000 BAD bloons. In a normal 100 round game, only a single BAD appears in round 100. In Alternate Bloons Round mode, only two [=BADs=] appear, one in round 99 and a fortified one in round 100. Like Sapper, going into high freeplay rounds is pretty much required unless you want to play a thousand games just for this achievement. This achievement became much more feasible with the addition of [[MookMaker Bloonarius]] boss events, as the Inflator's higher tiers spew out lots of [=BADs=] which count for the achievement.

** The [[https://bloons.fandom.com/wiki/Monkeyopolis Monkeyopolis]]'s income per crate being cut to two thirds in version 32.0 has already been a disappointment to the fandom, but the one down below tops the cake.

** In ''[=BTD6=]'', the Engineer's Sentry Expert upgrade allows the Engineer to build four types of sentries: laser, bomb, cold, and spiked balls; each with their own stats and damage types. It's also unique in that the Engineer will take into account what Bloons are on the screen to determine which sentry type to spawn. However, the next upgrade, Sentry Champion, scraps all that and return to only building one type of sentries, albeit a more powerful one. Many players have suggested Sentry Champion be changed to build more powerful versions of the Expert sentries instead of only building plasma sentries as it currently does.

* ViewerPronunciationConfusion: Geraldo's name is explicitly pronounced in a Spanish-like fashion in-game. However, as many players turn off hero voices, the pronunciation isn't very well-known among the playerbase.

** Australians as a whole also fall under this, as the Australian flag costs 60% more than other countries' flags in the Trophy Store for no real reason.

** Among players of Advanced Challenges, Primary Expertise and Bloon Solver are considered the mascots of [[SturgeonsLaw lazy and unoriginal challenges.]] The Bloon Solver is also mocked by other players for its CripplingOverspecialization at clearing Super Ceramics.

** 33.0's preview annoucement made public the controversial change to impose a 3-Paragon limit to promote creativity in choosing Paragons. After feedback from the community, this limit was changed to 4 Paragons while an additional Content Browser editor function that allows players to set higher limits or unrestricted in player made Content Browser games. This was followed by NK announcing that they would like to backpedal further by removing the limit outside of bosses and Contested Territory.

** 33.0's preview annoucement made public the controversial change to impose a 3-Paragon limit to promote creativity in choosing Paragons. After feedback from the community, this limit was changed to 4 Paragons while an additional Content Browser editor function that allows players to set higher limits or unrestricted in player made Content Browser games.

** When [[https://www.reddit.com/r/btd6/comments/y1rbkv/bloons_td_6_update_notes_version_330/ version 33.0]] added a limit to the amount of Paragons you can have and set it to 3, a ''massive'', still ongoing uproar happened on Reddit.

** When [[https://www.reddit.com/r/btd6/comments/y1rbkv/bloons_td_6_update_notes_version_330/ version 33.0]] added a limit to the amount of Paragons you can have and set it to 3, a ''massive'' uproar happened on Reddit.

** Bloontona 500 requires you to join 500 races. You get a free entry every three hours, and races run for three days a week. You can pay 100 Monkey Money to join a race again, but you get only ''250'' for the achievement, so it's definitely not worth it.

** The Legend of the Night, a Super Monkey upgrade, spawns a unique [[UnrealisticBlackHole rechargeable black hole attack]] that serves as a OneHitKill any sort of leak for 7.5 seconds upon escaping, recharging every two minutes. Not even [=BADs=], normally having ContractualBossImmunity to this sort of thing, are immune. Sadly, it sees virtually no use except in very few custom challenges specifically centered around this ability for two principal reasons. First, it is too expensive (costing over $200,000 ''on Easy Mode'') for non-freeplay rounds. Second, it is a required sacrifice for the powerful Avatar of the Vengeful Monkey, a tower essential to deep freeplay runs, and if you build such an Avatar, you cannot use the black hole ability ever again unless the Avatar is sold (which is obviously ill-advised). With the Legend of the Night being nigh-unusable in both freeplay and non-freeplay rounds, the black hole (an interesting anti-leak mechanic) goes underused. This became more so after Ninja Kiwi imosed various nerfs to the black hole (to prevent players from using ability cooldown modifiers to sit back and achieve massively hgih rounds).

** The Legend of the Night, a Super Monkey upgrade, spawns a unique [[UnrealisticBlackHole rechargeable black hole attack]] that serves as a OneHitKill any sort of leak for 7.5 seconds upon escaping, recharging every two minutes. Not even [=BADs=], normally having ContractualBossImmunity to this sort of thing, are immune. Sadly, it sees virtually no use except in very few custom challenges specifically centered around this ability for two principal reasons. First, it is too expensive (costing over $200,000 ''on Easy Mode'') for non-freeplay rounds. Second, it is a required sacrifice for the powerful Avatar of the Vengeful Monkey, a tower essential to deep freeplay runs, and if you build such an Avatar, you cannot use the black hole ability ever again unless the Avatar is sold (which is obviously ill-advised). With the Legend of the Night being nigh-unusable in both freeplay and non-freeplay rounds, the black hole (an interesting anti-leak mechanic) goes underused.

** In ''[=BTD6=]'', prior to patch 6.0, most players ended up using the combo of a top-path Alchemist buffing a bottom-path Super Monkey and a top-path Ninja. Even after the nerf that causes top-path alchemist buffs to expire after a specific amount of attacks and bottom-path Super Monkeys got nerfed as well, several towers attacked slow enough to still be extensively paired with top-path alchemists, such as (once again) top path ninjas, bottom path submarines, and top path wizards. And then come Update 17, the bottom path Super Monkey got Darkshift, which then proceeded to bring this strategy back a bit.

** Freeplay ventures in the fifth generation always used Temples of the Monkey God due to being heavily boosted by their sacrifices on top of their base power, allowing them to handle the gradually stronger blimps that Freeplay almost solely consists of. The Avatar of the Vengeful Monkey in ''Bloons TD 6'' is the go-to tower for freeplay attempts as well for the same reason.

* HypeBacklash: Despite months of excitement for the Engineer's Paragon in the buildup to its release in 32.0, the Master Builder was panned once it finally arrived. It overspecialises in the first path's sentry-based mechanics at the cost of abandoning nearly ''every'' other aspect of the second and third paths apart from buffing itself a la Overclock at the start of every round and being able to pin MOAB-class bloons in place, essentially making it a Paragon-level Sentry Champion. In conjunction with how versatile (and expensive) Ultraboost and XXXL Trap are, it is generally seen as far from a worthwhile upgrade, and players were already clamoring for Ninja Kiwi to rework it mere days after its release.

** Sapper in ''[=BTD6=]'', which requires popping a whopping ''five million'' Fortified or MOAB class Bloons. Unless you're willing to go for extremely high freeplay rounds, it will take over a thousand 100-round games to reach that number. Even worse, upgrades that remove Fortified status, such as the Mortar's Shattering Shells, don't count towards this achievement. It's often one of the last achievements obtained for players.