Late Game and Freeplay (BTD6)

A late game defense optimized to achieve the Bloon Master Populous Achievement.

Late Game and Freeplay are two distinct, yet often interchangeably used, terms in Bloons TD 6 describing high rounds.

Late Game (often capitalized) refers to the rounds near the end of the Hard, Impoppable, and Boss Rush gamemodes (usually between 75-100). However, Late Game also describes round 100+ as these rounds consist mainly of MOAB-class bloons and Super Ceramic rushes; these rounds are often referred by the latter term instead.

Freeplay (can be uncapitalized or with spacing) technically refers to rounds after the gamemode has been beaten and XP downscaling begins. So, Freeplay can begin on round 41 on Easy Mode, 61 on Medium, 81 on Hard, and 101 on Impoppable, C.H.I.M.P.S. and Boss Events. As a result, there is overlap in the definitions of Late Game and Freeplay.

After Round 80, rounds and bloons are subject to modified rules. They have been officially referred to as the freeplay rules.

A third term, Late Game Freeplay (used together), is used to specifically refer to extremely high rounds, conventionally after Round 263 (the last of the special rounds). The following sections detail this behavior and some general strategies to survive Late Game. As a result, the Late Game rounds can be divided as follows:

• Round 81-100: Impoppable and C.H.I.M.P.S. rounds
• Round 101-140: Predetermined Freeplay
• Round 141-162: Early Random Freeplay I
• Round 163: Break time
• Round 164-199: Early Random Freeplay II
• Round 200: Early-mid Freeplay (not random)
• Round 201-262: Middle Random Freeplay
• Round 263: Break time again
• Round 264+: Deep/Late Game Freeplay

In either case, this article will focus on Late Game and Freeplay past round 75.

Behavior

Freeplay Warning

General Freeplay Information

Freeplay begins once the final round is beaten. The cutoffs are

• Round 41 on Easy Gamemodes
• Round 61 Medium Gamemodes and Deflation
• Round 81 on Hard Gamemodes
• Round 101 Impoppable and CHIMPS

During freeplay, XP rewards are decreased to 30% of the original rate before round 100, and 10% after round 100.

General Late Game Behavior

Besides freeplay rules, there are thresholds where bloon spawning will guarantee certain bloon groups and reduced Cash generated from popping bloons.

Rounds 51+:

• Cash per pop starts to be reduced.

Rounds 81+:

• The freeplay rules apply from there on, ramping the MOAB-class bloons and changing the behavior of bloon descendants.
  • Ceramic bloons become super ceramics with 6x more health, but only one line of children. (They still give the same amount of money.) As a side effect, Purples, Leads, Ceramics, and MOAB-Class Bloons consume less lives than before freeplay rules and also take up less budget for Apopalypse.
  • MOAB-Class bloons slowly start gaining more HP and all bloons start getting faster.
  • Bloons start to gain common resistances to status effects deeper in freeplay.

Rounds 101+:

• Conventionally considered the start of freeplay regardless of game mode. The next forty rounds are still preset in both Standard Rounds and Alternate Bloons Rounds .
  • Boss Bloon Events can extend up to Round 120 with the arrival of fifth-tier bosses. At that point, the player has another 20 rounds to defeat the fifth-tier boss, as the game will end immediately in failure upon reaching Round 140.

Rounds 141+ :

• From this point, all rounds become randomly generated, except for rounds 163, 200, and 263.
• The round generation is limited by the RBE budget formula and the bloon groupings.
  • For Rounds 101-140, RBE budget is quadratic 17.5 * (Round^2).
  • For Rounds 141+, RBE budget is the linear (Round * 4,000) - 217,000. The RBE budget forms a continuous function.

Rounds 150+:

• Bloons start gaining status resistances regardless of type.

Rounds 201+:

• FBADs can now appear in random rounds after their "official" introduction in the special Round 200.
• From now on, subsequent BADs only consume 25,000 RBE budget and subsequent Fortified BADs only consume 50,000 RBE budget to increase in spawning BADs and Fortified BADs.

Rounds 231+:

• BADs are now guaranteed to spawn in every random round.

Rounds 251+:

• FBADs are now guaranteed to spawn in every random round.

Rounds 351+:

• By this point, all subsequent BADs only take up 1 RBE budget and subsequent Fortified BADs only take up 2 RBE budget, which means they are guaranteed BADs and Fortified BADs.

Rounds 511+:

• By this point, the final realistically reachable bloon groups, being stacks of 5 BADs and 5 FBADs with 0 spacing, are guaranteed to spawn throughout the round to make it considerably harder.

Round 624:

• By this point, the RBE budget can start to accommodate all freeplay bloon groups in a round.

Round 1758:

• By this point, the RBE budget is sufficient to accommodate all freeplay bloon groups for all future rounds. The freeplay bloon groups total to:
  • 96 MOABs
  • 64 FMOABs
  • 49 BFBs
  • 34 FBFBs
  • 40 ZOMGs
  • 26 FZOMGs
  • 56 DDTs
  • 60 FDDTs
  • 41 BADs
  • 38 Fortified BADs.

Rounds 1987:

• By this point, the first of two groups containing 100 FBADs begins spawning. They are guaranteed, which could indicate this as a soft round limit.

Rounds 10,000+:

• All rounds from there on spawns two groups of 100 FBADs, except for Round 10001 to Round 10005 where it spawns one group of lower rank bloons in order of first appearance, and except for farther arbitrary and hard limits.

Rounds 10,133,702+:

• No bloons spawn any more, as there are no bloon groups by this point.

Cash per Pop

Round 51-60 :

• Cash per pop is reduced to 50%

Round 61-85 :

• Cash per pop is reduced to 20%

Round 86-100 :

• Cash per pop is reduced to 10%

Round 101-120 :

• Cash per pop is reduced to 5%

Round 121+ :

• Cash per pop is reduced to 2%

HP Ramping

The HP ramping formula follows a continuous piecewise linear function in eight brackets.

NOTE: This does not affect their life lost when leaked.

Round 81-100 :

• MOAB class bloons' health now increase by 2% every round. (r81 : x1.02, r100 : x1.4).

Round 101-124 :

• MOAB class bloons' health now increase by 5% every round. (r101 : x1.45, r124 : x2.6).

Round 125-150 :

• MOAB class bloons' health now increase by 15% every round. (r125 : x2.75, r150 : x6.5).
  • Round 140 fortified BAD has 200,000 health and 429,920 RBE.

Round 151-250 :

• MOAB class bloons' health now increase by 35% every round. (r151 : x6.85, r250 : x41.5)
  • Round 200 fortified BADs have 960,000 health and 1,995,520 RBE each.

Round 251-300 :

• MOAB class bloons' health now increase by 100% every round. (r251 : x42.5, r300 : x91.5)

Round 301-400 :

• MOAB class bloons' health now increase by 150% every round. (r301 : x93, r400 : x241.5)

Round 401-500 :

• MOAB class bloons' health now increase by 250% every round. (r401 : x244, r500 : x491.5)

Rounds 501+ :

• MOAB class bloons' health now increase by 500% every round. (r501 : x496.5, rN : 5N-2008.5)

Speed Ramping

The speed ramping formula follows a piecewise linear function with discontinuities in five brackets.

Rounds 81-100:

• Every bloons' speed now increases by 2% every round. (r81: 1.02, r100: 1.4).

Round 101:

• At this point, the speed suddenly jumps to 1.6x faster than base speed. From this point onwards, the speed bonus for all bloons increases remains at +2% every round. (r101: 1.6, r150: 2.58).

Round 151:

• At this point, the speed suddenly jumps to 3x faster than base speed. From this point onwards, the speed bonus for all bloons increases remains at +2% every round. (r151: 3, r200: 3.98).

Round 201:

• At this point, the speed suddenly jumps to 4.5x faster than base speed. From this point onwards, the speed bonus for all bloons increases remains at +2% every round. (r201: 4.5, r251: 5.5).

Round 252:

• At this point, the speed suddenly jumps to 6x faster than base speed. From this point onwards, the speed bonus for all bloons increases remains at +2% every round. (r252: 6, rN: 0.02N+0.96)

Use this pseudocode programming language for better analysis:

    if (r <= 80) v = 1;
    else if (r <= 100) v = 1 + (r - 80) * 0.02;
    else if (r <= 150) v = 1.6 + (r - 101) * 0.02;
    else if (r <= 200) v = 3.0 + (r - 151) * 0.02;
    else if (r <= 250) v = 4.5 + (r - 201) * 0.02;
    else v = 6.0 + (r - 252) * 0.02;

And on Java:

    double r = 251;
    double v = 0;
    
    if (r <= 80) {v = 1;}
    else if (r <= 100) {v = 1 + (r - 80) * 0.02;}
    else if (r <= 150) {v = 1.6 + (r - 101) * 0.02;}
    else if (r <= 200) {v = 3.0 + (r - 151) * 0.02;}
    else if (r <= 250) {v = 4.5 + (r - 201) * 0.02;}
    else {v = 6.0 + (r - 252) * 0.02;}
    
    System.out.println(v);

Status Resistance

Being the last of the freeplay rules, bloons eventually receive global status resistances in the form of reducing the time duration where the status is in effect. They include:

• All Stun effects (including Cripple MOAB debuff)
• Bloon Sabotage and Grand Saboteur ability slowdown
• Snowstorm ability (Absolute Zero unaffected)
• All Knockback effects, except Press effects

Round 150-199:

• All statuses above has -10% duration of base.

Round 200-249:

• All statuses above has -20% duration of base.

Round 250-299:

• All statuses above has -30% duration of base.

Round 300-349:

• All statuses above has -40% duration of base.

Round 350+:

• All statuses above has -50% duration of base.

Strategies

There are many reasons a player would want or need to play Late Game or Free Play. Practical reasons include gamemode requirements. Players must be able to survive the grueling MOAB rushes of round 81-100 in order to beat C.H.I.M.P.S. and Impoppable. This is furthered in Boss Events, where late game towers are a necessity to combat round 100-140. Beyond these rounds, Late Game also provides an environment rich in RBE and MOAB spawns, perfect for obtaining achievements like Bloon Master Populous and Sapper. Another reason is that expensive upgrades like Super Mines, Legend of the Night, True Sun God, and Paragons are largely inaccessible until round 90+. Going into Freeplay allows players to experiment and push these towers to their upper damage limit. However, the most fundamental motivation for players venturing into freeplay is the sense of accomplishment for achieving a high round or pop count, and showing off to other players via their profile statistics.

Late game presents a number of challenges including dense MOAB rushes, high HP super-ceramics, and stun resistance. However, by far, the two biggest threats are high speed DDTs that can rush though a defense early in the round and BAD bloons which can not be stunned or slowed in any way, and can eventually cruise through any defense. Where early and mid-game rounds are focused on finding effective synergies and being efficient with income, a Late Game defense requires a fairly inflexible strategy centered around 5 critical aspects: Income, High Damage Per Second (DPS) towers, maximal buffing, MOAB stalling, and lag reduction.

To learn about these various strategies, see BTD6 Freeplay Mode/Strategies.

Trivia

• As of version 37.0 of BTD6, Round 536,928 is the first round to contain no bloons, due to a hard limit. Round 10,133,702 is the first round not define their bloon groupings, and marks the point where bloons permanently cease to enter. The round counter itself is a signed 32-bit value subject to its own hard limit.
• The highest legitimate round ever to be achieved in BTD6's Freeplay Mode prior to version 11.0 is round 3275 by nucleon_oz. Link.
• Bloon ramping has been made considerably more aggressive on version 11.0.
  • On version 11.0, rounds above 1100 were possible to be achieved due to a bug with Obyn Greenfoot hyperbuffing Vengeful True Sun God sun avatars.
  • Ever since the Obyn bug has been patched in version 12.0, rounds above 600 is extremely hard to legitimately accomplish.
  • There was an ongoing legitimate run on version 16.2, in which round 1000 was achieved. The strategy involves 23 Sun Temples and more than 30 Unstable Concoctions, taking advantage of the enormous health ramping of B.A.D's at higher rounds to set off chain reaction explosions. However, this results in massive performance drops and each round is said to take 40 minutes to complete, totalling at 270 hours to reach round 1000.
  • Hypothetically, one could have reached high rounds using an exploit in 31.0 involving getting more than one Paragon. This exploit however has been patched in the 32.0 update.
• Initially, all freeplay rounds were random rounds, like in Bloons TD 5.
  • Fortified Purple Bloons also spawned in the earlier random rounds only before the 2.0 update.
  • As of 26.0 update, standard rounds from 101 to 140 have been made pre-determined, they never occur in normal gameplay. They still appear on specific rounds, but with much larger spacing by "symbolized numbers". For example, Round 107 spawns 444 camo purples and Round 129 spawns 77 camo purples.
    • Because of this, now all bloons up to Ceramic Bloons are pre-determined during entire game.
    • As of 27.0 update, as the beginning stage of pre-determined standard freeplay rounds contains Fortified Leads, now rounds 101-120 in Apopalypse/ABR are able to spawn stack of 100 Fortified Leads with 0 spacing.
  • As of 44.0 update, Alternate Bloons Rounds 101-140 have been made pre-determined to catch up with the standard rounds. It is also a lot harder, especially on Round 120/ABR and Round 140/ABR.
    • As a result, now Round 140/ABR consists most amount of BADs up to Round 200, because Round 140/ABR spawns 1 BAD and 4 Fortified BADs (1+4*2=9), and Rounds up to 200 only spawn up to 7 BADs per round.
• Theoretically, The Navarch of the seas could get 884 billion pops in a real game (round 536928 challenge editor 2000% Moab hp) by taking down a fortified BAD using hook ability.
• Purple Bloons have the least RBE (6 RBE) of any freeplay Bloon, although many were stacked with 0 spacing. The freeplay bloon that has second least RBE is Fortified Lead Bloon (10 RBE).
• In BTD6, some Freeplay Rounds show resemblance to regular rounds that are 100 rounds before. For example, round 163 (many Lead Bloons and Ceramic Bloons) and round 63; round 200 (2 Fortified BADs) and round 100.
  • Some pre-determined freeplay rounds on rounds 101-140 also show resemblance to regular rounds that are 50 rounds before. For example, round 126 (Dense DDTs instead of regrow ceramics) and round 76; round 128 (Camo Fortified Ceramics instead of purples and rainbows, BFBs instead of ceramics, Fortified DDTs instead of camo ceramics) and round 78.
• In BTD6, the last random round that contains all MOAB-class bloons is round 9999. Starting on round 10000 and continuing from 10006 onwards, only Fortified BADs will spawn (always 200, split into two groups of 100). This marks the round limit of the game.
• As of Version 21.0 in BTD6, when the player loses in Freeplay Mode, instead of showing 'Defeat', the game will show 'Game Over' as well as a stat card similar to the one when the player wins, though the player can still continue if the game they're playing allows them to.
• There was a bug on Version 27.0 where every level after entering freeplay mode rewarded cash if the player exited to the main menu and reloaded the game. It was fixed shortly afterwards.
• Before update 37.0, some seeds would randomly crash the game. (full list here) Additionally, several other seeds crash on specific rounds; a total of 529 seeds were found to cause crashes, if the mentioned seeds occur on that round (initial seed + round - 1). Since there are 2^31 - 2 possible combinations, it is almost impossible to encounter these specific glitched seeds.
• The latest round you can encounter a BAD for the first time in the randomized rounds (outside of Apopalypse) is round 155. There is only one seed in the entire game that is able to do this.

Version History

2.0

• Fortified purple bloons no longer spawn.

8.0

• Additional Instamonkeys are now rewarded every 100 rounds completed in Freeplay.

9.0

• General minor difficulty increases for freeplay (unsure what exactly; more needs investigation)

11.0

• Freeplay difficulty scaling and bloon groupings have had a massive rework to be considerably more difficult. Only Rounds 101+ are affected.

17.0

• Removed Freeplay speed cap. BADs after the round limit can reach the exit in less than a second.

24.0

• Freeplay XP reduction before Round 101 reduced (-90% → -70%)

25.0

“	For more challenge consistency in high rounds, the standard roundset has been extended up to round 120. Now in game modes with standard roundsets the freeplay rounds from 101-120 will be predetermined. This is a big deal for us and we plan to do more custom rounds past 120, so we do want to hear feedback from the community here...	”
	~ Ninja Kiwi

• Freeplay rounds 101-120 now have a default round for each.
• Groups of hyperstacked purple bloons removed, however some rounds now contain dense DDT groups, considerably dangerous for most players

26.0

“	Freeplay rounds from 121 to 140 have now been added in the default round set, so like the recent 101-120 additions, these will now be consistent rounds. Interesting, I wonder if Ninja Kiwi is up to something...	”
	~ Ninja Kiwi

• Freeplay rounds 121-140 now have a default round for each.
• Round 140 now features Fortified BAD (requires twice as more damage to pop, but income unchanged; considerably harder for most players without specific strategy)

27.0

“	...and also roughly easing up on the freeplay health ramping of MOABs by a similar amount	”
	~ Ninja Kiwi

• Freeplay formula for MOAB Health Increase from round 125-150 reduced from 0.20 → 0.15
• Freeplay formula for MOAB Health Increase from round 151-250 reduced from 0.50 → 0.35

33.0

“	To encourage challenge diversity using the new extended list of preset rounds in freeplay, we have decided to make a tweak to freeplay income tax to drop it off slightly slower and allow a little more cash to be earned naturally in this range.	”
	~ Ninja Kiwi

• Round 101-120 natural income generation increased from 2% → 5%. Round 121+ natural income generation remains at 2%.

37.0

• Freeplay budget scaling reduced slightly (by up to 20%)

44.0

• Alternate Bloons Rounds 101-140 are now preset rounds which are considerably harder than both the former random rounds and their Standard and Apopalypse counterparts.
  • Now some rounds without DDTs in Standard Rounds spawn DDTs, and there are extra guaranteed BADs in Alternate Bloons Rounds
  • Round 106 in Alternate Bloons Rounds now spawns a BAD, which isn't allowed to spawn during randomized rounds before Round 110 in Apopalypse
  • Round 120 in Alternate Bloons Rounds now spawns a Fortified BAD, and Round 140 in Alternate Bloons Rounds now spawns Fortified BAD and BAD at the same time, after a while it spawns 3 Fortified BADs in a short duration, which is the fastest BAD spawn rate in the game up to Round 200. (since randomized rounds don't contain Fortified BADs prior to Round 200)
  • Some clumped Purple groups are replaced by DDTs in Alternate Bloons Rounds to make it harder.

46.0

RBE Budget in freeplay rounds changed, and is now more uniformly distributed