Engineer Monkey (BTD6)

Overview

BTD5

BTD6

BTDB2

Engineer Monkey
General Information
Game	Bloons TD 6 (v12.0)
Release Date	September 18th 2019
Class	Support
Unlocked at	Level 22-24 and Level 26
Cost	$300 (Easy) $350 (Medium) $380 (Hard) $420 (Impoppable)
Activated Ability(s)	Overclock Ultraboost
Targeting Options	First, Last, Close, Strong, Manual Targeting with Cleansing Foam or 0-1-4 Bloon Trap
Hotkey	L
Other Names	Engi, Engineer
Statistics
Damage	1
Pierce	3
Attack Speed	0.7s
Range	40
Status Effects	Requires upgrades
Tower Boosts	Requires upgrades
Income/Life Boosts	Requires upgrades
Camo Detection	Yes (x-3-x, only decamo via foam)
Footprint	Medium (7)
Default Damage Type	Sharp
Related Towers
Monkey Engineer (BTD5), for the BTD5 counterpart Engineer Monkey (BTDB2), for the BTDB2 counterpart

“	Holds a trusty nail-gun to pop the Bloons. Can upgrade to create its own nail-shooting sentry turrets.	”
	~ In-game description

The Engineer Monkey is a Support-class tower added in Version 12.0 of Bloons TD 6 on September 17, 2019. The tower received a name-change from Monkey Engineer, but retains its role from the Bloons TD 5 Generation, with significant additions.

It was first teased on social media (specifically on Twitter and Reddit) just before Version 12.0 was released several days later. On Reddit, it was teased here, on September 15th 2019.

The base Engineer Monkey wields a nailgun that shoots nails at bloons. It shoots one nail every 0.70s, dealing 1 damage (sharp), and starts with a base range of 40. The main power of the Engineer comes from contraptions and other applications of mechanical engineering, accessed by upgrades. It can be upgraded to produce sentries of various types, Cleansing Foam to pop lead and decamo bloons, and Bloon Traps to instakill a certain amount of bloons. It can also be upgraded to boost other towers by the use of a power wrench, amplifying the attack speed of its targets with Overclock.

It costs $300 on Easy, $350 on Medium, $380 on Hard, and $420 on Impoppable.

Description

The Engineer Monkey features a yellow hard hat as it did back as Monkey Engineer in BTD5. Its nailgun is smaller than its BTD5 counterpart, and is colored yellow. Because of the nailgun's smaller size, it only needs to hold it with just its right hand instead of with both hands.

Path 1 focuses on damage and deployment of Sentries. It allows Engineer to build secondary towers as decent backup defense, with further upgrades increasing their effectivity. Sentry Expert allows the engineer to build specialized sentries to add versatile support against certain bloons. Its 5th tier Sentry Champion allows building of very powerful unstable sentries that before disappearing explode, dealing huge damage to nearby bloons.

Path 2 focuses on support. Larger service area allows the engineer to shoot from a longer range, while Deconstruction improves MOAB and Fortified damage. Cleansing Foam removes Camo and Regrow properties off bloons, Overclock allows the engineer to temporarily increase attack speed of targeted tower by 66%. (Duration varies by tier of tower) (For banana farms it increases income and for villages it increases influence radius). Ultraboost adds permanent 6.6% to overclocked tower that stacks up to 10x for maximum of 66% permanent increase.

Path 3 focuses on a combination between stalling and cleanup. Its Pin upgrade allows the engineer to pin any non-moab class bloon expect for ceramic and lead, temporarily stopping it from progressing for short time. Bloon Trap allows any non-moab class bloon to be trapped until it is full which can be manually collected (with some bonus cash). Its 5th tier XXXL Bloon Trap significantly increases the capacity and can also trap Moab class bloons (excluding B.A.D).

The Engineer Monkey Paragon, the Master Builder, is the final upgrade for all three paths. It incorporates most features of the Engineer, with notable exceptions including foam and traps.

Target Priorities

The base Engineer Monkey uses the standard target priorities: First, Last, Close, Strong. Most of the Engineer's alternate attacks do not integrate its own target priority.

• First: Targets the first bloon visible within its range.
• Last: Targets the last bloon visible within its range.
• Close: Targets the closest bloon visible within its range.
• Strong: Targets the strongest bloon visible within its range.

All of the Engineer Monkey's alternate attacks have a different set of target priorities:

• Sentry spawning tends to follow based on the Engineer's perception of where bloons will most likely move around. Hence, sentry spawning depends slightly on RNG but is not entirely RNG-based. Sentry spawns also attempt to only target unoccupied areas of the map. If there are many towers within range of the Engineer blocking potential land spots, the Engineer will spawn sentries between the space of other towers.
• Sentries themselves start with the target priority of the main Engineer at the time of spawning. Individual sentries must have their target priority changed manually from their current target priority.
• Cleansing Foam location is able to be chosen by the player. Foam is placed on Close by default.
• Overclock and Ultraboost abilities require user input to pick the tower to boost.
• Bloon Traps and XXXL Traps are always placed on Close regardless of the Engineer's own target priority, unless Larger Service Area is bought. Then the player may choose a place in range of the engineer to place it.

Upgrades

Path 1

	Sentry Gun COST: $425 / $500 / $540 / $600 UNLOCK: 160 XP
	Description: Creates temporary sentry guns and deploys them nearby. Effect: Produces temporary sentry guns onto nearby land. Sentry Guns pop up to 2 bloons per shot, lasts for up to 25 seconds before disappearing, and can be improved with crosspathing.

	Faster Engineering COST: $340 / $400 / $430 / $480 UNLOCK: 550 XP
	Description: Increased efficiency allows the Engineer to produce sentries, foam and bloon traps more often. Effect: Produces all contraptions +66% faster (0.60x attack cooldown).

	Sprockets COST: $490 / $575 / $620 / $690 UNLOCK: 1,850 XP
	Description: Increases sentry gun and Engineer attack speed. Effect: Nailgun and newly deployed sentry guns attack twice as fast.

	Sentry Expert COST: $2,125 / $2,500 / $2,700 / $3,000 UNLOCK: 9,500 XP
	Description: Sentries deploy with different damage types based on your need. Effect: Replaces all new sentries with four specialized sentries: Crushing, Boom, Cold, and Energy. Adjusts deployment of these four sentry types depending on bloons on the screen.

	Sentry Champion COST: $27,200 / $32,000 / $34,560 / $38,400 UNLOCK: 30,000 XP
	Description: Creates super-powerful but highly unstable sentries. Effect: Replaces all new sentries with powerful plasma sentries that shoot plasma 15 times per second that have 5 pierce and 3 damage. The sentries can pop Frozen and Lead but cannot pop Camo or Purple. Expired sentries now explode a wave of plasma after 25 seconds or when sold, instead of disappearing.

Path 2

	Larger Service Area COST: $210 / $250 / $270 / $300 UNLOCK: 170 XP
	Description: Shoots further and deploys sentries in a much larger area. Sentries have longer range Effect: Engineer gains +20 range and any newly deployed sentries gain +4 range. Allow newly placed selectable placement for Bloon Traps.

	Deconstruction COST: $295 / $350 / $380 / $420 UNLOCK: 500 XP
	Description: Nail gun and Sentry shots do extra damage to MOAB-class and Fortified Bloons. Effect: Nailgun and newly deployed sentries deal +1 damage to MOAB-class and +1 damage to Fortified.

Cleansing Foam COST: $765 / $900 / $970 / $1,080 UNLOCK: 2,000 XP

Description: Sprays foam that removes Camo and Regrow and pops Lead Bloons. Effect: Sprays foam anywhere on nearby bloon track. Bloons that hit the foam will permanently lose Camo and Regrow properties. Deals 1 damage to any passing Lead Bloons. If crosspathed with Sentry Gun, sentries shoot foamy nails that apply foam effect on hit bloons. If crosspathed with Pin, foam slows every non-blimp bloon by 50%. In addition, attacks 4x faster for the first 1 seconds of a round.

	Overclock COST: $11,475 / $13,500 / $14,580 / $16,200 UNLOCK: 14,000 XP
	Description: Overclock Ability: Target another tower to supercharge its attack speed for a short time. Effect: Ability temporarily increases attack speed of tower, range of a Monkey Village, or production of a Banana Farm. Ability duration depends on tier of the selected tower. Main attacks gains more pierce.

	Ultraboost COST: $61,200 / $72,000 / $77,760 / $86,400 UNLOCK: 35,000 XP
	Description: Ultra-Overclocked Monkeys gain a small but permanent boost every time they are overclocked. Effect: Ability now permanently applies a 10th of the bonus of Overclock onto the selected tower, stacking up to 10 times. Ability cooldown reduced to 35 seconds. Main attack gains even more pierce.

Path 3

	Oversize Nails COST: $380 / $450 / $485 / $540 UNLOCK: 150 XP
	Description: Massivization allows nails to pop 8 Bloons at once, including frozen. Also increases Foam and Sentry effectiveness. Effect: Nailgun pierce increases from 3 to 8. Pierce of regular sentries increased from 2 to 3 and foam increased from 10 to 15.

	Pin COST: $185 / $220 / $235 / $265 UNLOCK: 500 XP
	Description: Pins Bloons in place for a short time when struck. Effect: Nailgun nails pin any non-blimp bloon other than Leads and Ceramics. Can give Pin effect to sentries with Sprockets or above. Also lets Cleansing Foam slow down any non-blimp bloons.

	Double Gun COST: $380 / $450 / $485 / $540 UNLOCK: 1,800 XP
	Description: Two guns for twice the fun. Effect: Double nailgun attack speed.

	Bloon Trap COST: $3,060 / $3,600 / $3,890 / $4,320 UNLOCK: 11,000 XP
	Description: Bloon trap captures Bloons until full. Select to empty full trap for cash. Effect: Produces a Bloon Trap that captures up to 500 RBE worth of non-blimp bloons. Manually collecting the full trap earns a bonus +100% income compared to popping them normally. Bloon Traps can only trap bloons it can target. Middle path crosspath allows traps to be manually adjusted, autocollecting them.

XXXL Trap COST: $40,800 / $48,000 / $51,840 / $57,600 UNLOCK: 40,000 XP

Description: Huge Bloon traps can trap some of the largest Bloons in them... Effect: Produces a huge XXXL Bloon Trap that captures up to 10,000 RBE worth of all bloon excluding BADs, Bosses, and undetected Camo. There is a 2 second cooldown between each trap that starts when placed. Manually collecting the full trap earns a bonus +100% compared to popping them normally. Only one XXXL trap can be on screen at any time per player.

Paragon

Master Builder COST: $552,500 / $650,000 / $702,000/ $780,000 UNLOCK: 750,000 XP

Description: Monkey engineering developed to perfection. Creates three Mega Sentries that can build their own sentries. Effect: Upgrades into a four-armed supersonic nail-shooting machine that produces three permanent specialized Mega Sentries (Green, Red, Blue) that themselves produce their own temporary miniature Modified Paragon Sentries (stronger versions of Champion Sentries). Nails deal enormous damage and can stun MOAB-class bloons. Can manually place Mega Sentries on any land location. Also overclocks itself at the start of each round.

Total Costs

Note: these numbers refer to Medium Mode.

		Tier 1	Tier 2	Tier 3	Tier 4	Tier 5
Path 1
	Base Cost	500	400	525	2,500	32,000
	Cumulative Cost	700	1,100	1,625	4,125	36,125
	Base Sell	350	630	2,185	2,748	25,138
	Cumulative Sell	665	945	2,500	3,063	25,453
Path 2
	Base Cost	250	350	800	13,500	120,000
	Cumulative Cost	700	1,050	1,850	15,350	135,350
	Base Sell	175	420	980	10,430	94,430
	Cumulative Sell	490	735	1,295	10,745	94,745
Path 3
	Base Cost	450	220	500	3,500	54,000
	Cumulative Cost	900	1,120	1,620	5,120	59,120
	Base Sell	315	469	819	3,269	41,069
	Cumulative Sell	630	784	1,134	3,584	41,384

Strategy

See also: Engineer Monkey (BTD6)/Strategies

Summary

Engineer Monkeys contain various lower-tier and higher-tier upgrades that are specifically geared to support the defense, typically offering strong indirect roles for the defense via their various sentries and other contraptions. An Engineer Monkey is typically best paired with additional defenses to make use of their supporting roles, but also possess many powerful upgrades that focus on DPS as well as support.

Tips

• Engi + Dart is a solid early-game on CHIMPS, with Engi doing most of the group-popping and Dart offering a little extra popping of stray bloons.

Monkey Knowledge

This section displays Monkey Knowledge that has effects on Engineer Monkey and its changes when compared to one by default:

• Vigilant Sentries: Sentry Turrets last longer than normal.
  • Increases Sentry Gun lifespan from 25 seconds to 30 seconds. Applies to all Sentries, including from Sentry Expert and Sentry Champion.
• Monkey Education: All Monkeys XP earn rate increased by 8%.
• Thicker Foams: Cleansing Foam can hit 3 more Bloons before expiring.
  • Increases pierce of each base cleansing foam blob from 10 to 13.
  • With Oversize Nails, cleansing foam blobs increase pierce from 15 to 18.
• Better Sell Deals: All Monkeys sell for 5% more.
  • Increases sell potency from 70% to 75%.
• Big Traps: Bloon Trap can hold up to 530 RBE.
• Veteran Monkey Training: All Monkeys reload time reduced by 3%.
• Global Ability Cooldowns: All Ability cooldowns for all Monkeys reduced by 3%.

Teasers

Engineer first teaser

It was teased a few days earlier on Reddit via r/btd6, on September 15th 2019, before the Version 12.0 update. Other teasers posted on Ninja Kiwi's Twitter, more than in r/btd6, the first one of an Engineer driving a truck (link), and the second is the Engineer carrying a toolbox full of tools (link). Both of these posts tease the Engineer Monkey.

The first Twitter teaser was accompanied by "Your delivery has been shipped." and was tagged with the following hashtags: #btd6, #BloonsTD6, #NinjaKiwi. Likewise, the second Twitter teaser was accompanied by "The anticipation is building 🐒🎈", followed with these hashtags: #BloonsTD6, #btd6, #NinjaKiwi.

Version History

Listed are comparisons of thecurrent (44.1) Engineer Monkey in BTD6 compared to BTD5. Takes into account Flash and Mobile versionse.

• Sentries no longer consume Footprint.
• Bloon Trap now has decreased income gain dependent on round income penalty, similar to BTD5 Deluxe and Monkey City Flash.
• Several changes in path placement of the upgrades. Sprockets is now a Path 1 Tier 3 upgrade, Cleansing Foam is now a Path 2 Tier 3 upgrade, Bloon Trap is now a Path 3 Tier 4 upgrade, and none of these upgrades may be bought on the same tower.
• Cleansing Foam now has less pierce (30 → 10).
• Bloon Trap now has a longer placement cooldown whenever trap is destroyed (~1.0s → ~2.8s)
• For each round when that trap still stays on the map, Engineer will store another Bloon Trap on itself, and the effect stacks with the number of rounds passing per Engineer. When all Bloon Traps are used during a later round, Engineer won't spawn another until next round.(???)
• Larger Service Area upgrade costs less ($650 → $550???).
• Sprockets upgrade costs less ($550 → $525).
• Overclock ability now has an initial cooldown of 15 seconds before usage when the upgrade is first purchased.
• Overclock ability can now target itself.
• Overclock ability duration decreases to 45s for T5 towers (who doesn't exist in btd5, but idk.
• Bloon Trap now traps more RBE (250 → 500).
• Sentries also can applies any upgrade not just engineer (???)
• Large service area now gives extra range to sentries
• Bloon trp can be spawned in a selected point if have large service area
• Cleansing has more pierce if it have oversized nails
• CLeansing foam with sentries now spawn cleansing sentries

Balance Changes

12.0 (Engineer Monkey Update)

Note: Lists all balance changes implemented for the Engineer Monkey when it was first released in Bloons TD 6 (September 18th 2019) in comparison to Bloons TD 5. Takes into account Flash and Mobile versions of Bloons TD 5.

• Sentries no longer consume Footprint.
• Sentries now have 1 pierce per nail instead of 2.
• Bloon Trap now has decreased income gain dependent on round income penalty, similar to BTD5 Deluxe and Monkey City Flash.
• Several changes in path placement of the upgrades. Sprockets is now a Path 1 Tier 3 upgrade, Cleansing Foam is now a Path 2 Tier 3 upgrade, Bloon Trap is now a Path 3 Tier 4 upgrade, and none of these upgrades may be bought on the same tower.
• Cleansing Foam now has less pierce (30 → 10).
• Bloon Trap now has a longer placement cooldown whenever trap is destroyed (~1.0s → ~5.0s) and is limited to 1 per round. The XXXL Trap upgrade can still place unlimited Traps.
• For each round when that trap still stays on the map, Engineer will store another Bloon Trap on itself, and the effect stacks with the number of rounds passing per Engineer. When all Bloon Traps are used during a later round, Engineer won't spawn another until next round.
• Larger Service Area upgrade costs less ($650 → $550).
• Sprockets upgrade costs less ($550 → $525).
• Overclock ability now has an initial cooldown of 15 seconds before usage when the upgrade is first purchased.
• Overclock ability can now target itself.
• Overclock ability duration decreases to 45s for towers valued between $15,000-$39,999, and to 30s for towers valued $40,000+.
• Bloon Trap now traps more RBE (250 → 500).

14.0

• 4-x-x Sentry Expert Energy Sentry damage increased from 1 to 2.
• 4-x-x Sentry Expert Bomb Sentry damage increased from 1 to 2.
• 4-x-x Sentry Expert Bomb Sentry attack rate increased from 1.5s to 1.4s.
• 4-x-x Sentry Expert Spiked Ball attack rate increased from 1.25s to 1s.
• 5-x-x Sentry Champion explosion damage increased from 70 to 85.
• 5-x-x Sentry Champion manually sold sentries will now explode with no animation delay.
• x-4-x Overclock reload time reduction lowered from -50% to -40% (farms remain 2x speed and villages still receive 25% range).
• x-5-x Ultraboost permanent reload time reduction lowered to -4% for a maximum of -40%.

15.0

• 1-x-x Standard Sentry pierce increased from 1 to 2.
• 4-x-x Sentry Expert price reduced from $2,800 to $2,500.
• 5-x-x Paragon Sentry pierce increased from 3 to 5.

18.0

• Sentry Expert's Boom Sentry blast radius increased (12 → 18).
• Sentry Expert's Boom Sentry attack speed increased (1.4 → 1.3).

20.0

“	Continuing our efforts to make crosspaths meaningful and fit the style of each path more solidly, a number of crosspath and base level balance shifts were made.	”
	~ Ninja Kiwi

• 1-1-0 Larger Service Area now applies 1/5th the range (+4) to any sentries produced.
• 1-0-1 Oversize Nails allows sentries produced by this tower to pop frozen Bloons.
• 1-0-1 Oversize Nails now increases sentry pierce by +1.
• 2-x-x Faster Engineering sentry deployment rate increased further from 7s to 6s.
• 4-x-x Sentry Expert base range of all sentries increased from 45 to 50.
• 5-x-x Sentry Champion explosion radius now scales with sentry radius.
• x-4-x Engineer Overclock ability active buff state will now be included in save files.
• x-5-x Ultraboost will now apply 'perma' stacks upon ability activation rather than expiration.

21.0

“	Engineer is quite poor in terms of crosspathing, so we've added crosspath benefits to Cleansing Foam as well as an overall price buff to the middle crosspathing upgrades. We've been somewhat unhappy with how Overclock sits in the game for a while and especially how the interaction with tower cost causes levelling heroes naturally to be far advantageous over purchasing upgrades when this is already underused. We have made an attempt to rework these issues by moving it to a tier-based system rather than price.	”
	~ Ninja Kiwi

• 5-x-x Sentry Champion explosion damage increased from 85 → 100.
• 0-1-0 Larger Service Area price reduced from $550 → 250.
• 0-2-0 Deconstruction price increased from $200 → 350.
• 2-3-0 Faster Engineering increases Cleansing Foam rate 2 → 1.2.
• 0-3-1 Oversize Nails increases Cleansing Foam pierce 10 → 15.
• Banana Farms give 66.7% more income instead of 100%.
• Overclock ability is reworked to operate on a tier basis rather than a cost basis:
  • T5 duration is now always 30 seconds.
  • T4 duration is now always 45 seconds.
  • T3 duration is now always 60 seconds.
  • T2 duration is now always 75 seconds.
  • T1 duration is now always 90 seconds.
  • T0 duration is now always 105 seconds.
  • Hero duration is based on X/4, where X is level, starting from Level 0 (i.e. Level 1-3 is T0, Level 4-7 is T1, Level 8-11 is T2, Level 12-15 is T3, Level 16-19 is T4, Level 20 is T5).

22.0

“	Bloon Trap can now be used more effectively.	”
	~ Ninja Kiwi

• If all of an Engineer's stockpiled Bloon Traps are used up, Bloon Trap now has a cooldown of 20s instead of only capping at one new trap per round. Bloon Trap cooldown now starts upon once it spawns rather than once it is collected. Does not affect the existing 2.8s cooldown while refreshing a trap.
  • Note: Bloon Trap is still limited to 1 at a time per Engineer.
• 2-0-4 Faster Engineering reduces the bonus Bloon Trap cooldown from 20s → 16s. Does not affect the existing 2.8s cooldown per trap.
• XXXL Trap will cooldown at 1/6th of the rate of the standard Bloon Trap.
  • XXXL Trap cooldown is now increased from 2.8s to 3.33s.
  • Note: Bloon Trap's minimum deploy time of 2.8s will override 205 Trap's 2.7s cooldown.

23.0

“	Sentry Expert has underperformed for a while, so we're adding solid crosspathing buffs to all Sentries. We've added a pierce & speed boost to Overclock's base upgrade and lowered the cooldown on Ultraboost to allow the possibility for it to achieve full uptime as a freeplay tower and get its stacks up faster. Finally last update we allowed Bloontrap to be set multiple times per round, and we wanted to stay on the side of caution with a long cooldown, but after seeing it in the wild we are happy to make this cooldown faster.	”
	~ Ninja Kiwi

• Deconstruction now grants all spawned Sentries with +1 damage to MOAB-class and +1 damage to Fortified.
• 4-0-1 Sentry expert now increases sentry pierce by roughly 25% instead of +1.
• 4-0-1 Crushing Sentry pierce increased (22 → 28).
• 4-0-1 Bomb Sentry pierce increased (30 → 38).
• 4-0-1 Cold Sentry pierce increased (15 → 19).
• Overclock's main attack's projecitle speed increased (375 → 750).
• Overclock's main attack's pierce increased (3 → 15).
• Ultraboost's main attack's pierce increased (3 → 30).
• Ultraboost ability cooldown reduced (45s → 35s).
• [undocumented] Ultraboost ability initial cooldown reduced (15s → 5s).
• Base Bloon Trap rate increased (20s → 15s).
• 2-0-4 Bloon Trap rate bonus increased (0.8x → 0.6x, or +25% → +66%).

25.0

“	Engineer XXL [sic] trap is extremely powerful but too expensive for backline dps and we'd like to see it more viable for frontline engineer builds.	”
	~ Ninja Kiwi

• XXXL Trap price reduced from $60,000 → $54,000.

26.0

“	It has been clear that Sentry Expert needs changes, with Cryo sentries the only ones that really seemed valuable and purposeful, so all of the others have been improved to fit their role. Additionally higher tier sentries will now be able to benefit from the xx2 Pin crosspath, so enjoy some laser pins. Bloon Trap redeployment rate has also been buffed a fair amount.	”
	~ Ninja Kiwi

• 4-x-0 Laser Sentry gains pierce increased from 4 to 8.
• 4-0-1 Laser Sentry gains pierce increased from 5 to 10.
• Ball Sentry damage increased from 1 to 2.
• Ball Sentry attack cooldown increased from 1s to 1.1s.
• Boom Sentry attack cooldown reduced from 1.3s to 0.9s.
• 3-0-2 Sentries & Higher will now also be able to Pin Bloons they pop.
• Bloon Trap redeployment cooldown reduced from 15s to 12s.
• [undocumented] XXXL Trap minimum cooldown is now reworked to scale properly with attack speed buffs. Therefore, new minimum cooldown is reduced from a fixed 2.8s to a flexible 2.0s.

28.0

“	Alright, Sentry Paragon is now a Champion.	”
	~ Ninja Kiwi

• Sentry Paragon renamed to Sentry Champion to differentiate it from Paragons.

29.0

“	Engineer's bottom 2 paths have a heavier support focus, so to start them off a bit easier we have shifted some starting cost out and into the non-supportive path. For the sake of further improved crosspath potential, we have also re-envisioned the 'Larger Service' crosspath as giving smarter service as well in the form for targeting for Bloontrap & Cleansing Foam	”
	~ Ninja Kiwi

• Base price reduced from $450 → $400
• Sprockets price increased from $525 → $575
• Cleansing Foam now defaults to Close instead of randomly placed
• Cleansing Foam now gains special targeting. Special targeting allows for placement anywhere within direct range.
• Bloon Trap with Larger Service Area now gains special targeting for the traps. Special targeting allows for placement anywhere within direct range.

30.0

“	To add a bit of quality of life solving problems with trap needing to fill once before moving to target location, Bloontraps placed off-track never being able to fill, and maybe even to just add some interesting micro, any Bloontraps will now become expired after a short delay when their Engineer has a new target set.	”
	~ Ninja Kiwi

• 0-1-4 Bloon Trap now refreshes upon pressing a new location; picking new target expires current trap and places new one. Still abides the cooldown rule for traps. Also affects 0-1-5 XXXL Trap.

31.0

“	Sentry Expert really needed some logic fixes to get more of the actual correct sentries placed at the right times, it has also received a number of power buffs across the board to the special sentries at T4 complimenting the new logic reworking. Cleansing Foam has had some extra crosspath utility added at the cost of a small price increase and a large decrease to Ultraboost price.	”
	~ Ninja Kiwi

• Sentry Expert logic has been reworked to evaluate threat levels based on Bloon types that it can counter, Bloon types that counter the sentries that it wants to spawn, and which of the current threats on screen is the greatest. Distribution of sentry types should scale based on how much one Bloon threat is more of a threat than another.
• Sentry Expert Crush Sentry ceramic damage bonus increased from 1 -> 4
• Sentry Expert Crush Sentry damage type changed from Sharp -> Shatter
• Sentry Expert Bomb Sentry damage increased 2 -> 4
• Sentry Expert Cold Sentry pierce increased from 15 -> 25
• Sentry Expert Cold Sentry radius increased from 12 -> 18
• Sentry Expert Energy Sentry gain moab damage bonus of +2
• Cleansing Foam price increased from 800 -> 850
• Pin allows Cleansing Foam to slow Bloons 50% briefly
• Foam makes Sentries shoot Foamy nails that strip properties
• Ultraboost price decreased from $120,000 -> 105,000

32.1

“	Yes, Ultraboost had to be changed for now in response to exploits. Not a fan of that either and will be looking for a better long term solution, but it was 'the' change that could easily be made with no risk and there are far more important things to put our time into fixing right now.	”
	~ Rohan, Version 32.1 comment

• Ultraboost ability is now capped at 3 uses per round

33.0

“	The MOAB offense of top path lacks for a mainly dps tower that is quite complex to use, T3 Sprockets already feels underwhelming so is seeing a buff here carrying up to T4, and the 320 crosspath will now be able to double dip on the Fortified & MOAB damage bonuses that it gains. Cleansing Foam is only seeing a slight tweak to help it be more viable if you want to attempt it as 'main camo detection’, and this mainly fixes some issues in ABR games allowing it to catch quick initial camo spawns.	”
	~ Ninja Kiwi

• Sprockets nailgun attack speed bonuses increased (+66% → +100%)
• Sprockets sentry nail attack speed bonuses increased (+66% → +100%)
• Note: Ninja Kiwi incorrectly listed the attack speed bonuses as a buff to the production rate; it is actually a buff to the attack speed bonuses granted to the nailgun and sentry nail attacks.
• 1-2-0 Sentries can now benefit from both of the moab and fort damage bonuses on one target if that target is a fortified moab
• Cleansing Foam attack gains 1s of 4x rate on round start

34.0

“	Overclock's considerable longer duration benefit on lower tiers currently serves little purpose and only leads to weirdness in upgrading boosted towers, so for now we’d rather minimize this on the early cases that don’t serve much purpose.	”
	~ Ninja Kiwi

• Overclock now no longer has longer ability duration for below T3 tower or Level 12 Hero

35.0

{{quote|Sentry Champion’s pierce crosspath does not feel like it has enough of an edge to compete with the deconstruction crosspath. Engineer Ultraboost is limited to viable use in high-farming situations due to its cost, and while the buff is great when applied to strong towers, we find it too expensive for an upgrade that only adds a buff to other towers, especially in games where cost is the primary focus.

• Ultraboost price reduced $105,000 -> $72,000

36.0

“	XXXL Trap 205 crosspath hasn’t actually ‘been working’ due to the base attack rate being faster than minimum deployment delay so we have slowed the base rate to make 205 crosspath actually matter. Along with this, since the fortification bonus aspect of x2x hasn’t ever done anything for Bloontraps, 024 will now ignore the fortification of Bloons that it eats	”
	~ Ninja Kiwi

• 0-2-4 Bloon Trap's RBE consumption now ignores Fortified properties.
• 0-2-5 XXXL Trap trap RBE consumption now ignores Fortified properties.
• 0-x-5 XXXL Trap deploy rate reduced from 2.8s → 5.8s
• 2-0-5 XXXL Trap deploy rate reduced from 2.8s → 3.48s (now actually increases deploy rate by 0.60x)

37.0

“	The 005 crosspath fix in the last update left XXXL Trap slower than previously even if crosspathed to 205, so we are increasing that base 005 slightly to match up the 205 crosspath again so that it isn’t any slower than before.	”
	~ Ninja Kiwi

• 0-x-5 XXXL Trap attack cooldown reduced 5.8s → 4.6s
• 2-0-5 XXXL Trap attack cooldown reduced 3.48s → 2.76s

39.0

“	Applying pierce crosspathing to Sentry Champion only granting an abysmal +1 pierce to the explosion while an intended joke at the time still feels a little silly, we’re separating that up to get its own larger increase now. Some extra of a makeup buff for XXXL, while the crosspathing rework itself feels nice it ended up nerfing the high-level micro play of this upgrade far more than intended.	”
	~ Ninja Kiwi

• 5-0-1 Sentry Champion explosion pierce increased (51 → 70)
• XXXL Trap price reduced ($54,000 → $48,000)

41.0

“	Improvements for Sentry Expert AI based on your feedback. Some minor QoL buffs for Ultraboost as it's very expensive over multiple T4s. Lastly Bloontrap was rather unfairly able to steal all cash in Co-op games; we want to avoid dividing one player's farm earnings between the group entirely, but decided on a compromise here to prevent it from stealing that base amount.	”
	~ Ninja Kiwi

• Sentry Expert should react with less Cold Sentries in response to Pink Bloons, and prioritize a more for AoE cleanup (i.e. slightly prioritizes greater for Bomb Sentries)
• Sentry Expert should react with less Energy sentries in response to Blue MOABs, and prioritize a more for Ceramic cleanup (i.e. slightly prioritizes greater for Cold and Crushing Sentries)
• Ultraboost cleansing foam pierce increased from 10 to 30
• Ultraboost ability now has full duration on T4s, duration increased from 45s to 60s
• Ultraboost ability now has full duration on T5s, duration increased from 30s to 60s
• Bloon Trap now divides the base value of absorbed Bloons between all players when collected, any extra multiplied value is fully granted to the owner of the Bloon Trap. Also affects XXXL Trap.

43.0

“	While better than many options, base Engineer still takes a lot of available starting cash so the cost is reduced slightly and being moved back up into Cleansing Foam & Bloontrap; also with a reduction to Double Gun’s price to reflect the lower value of the base tower. Sentry placements are slightly changing to improve their reliability, and will now spawn closer to the track depending on how much range the sentry has. Sentry Champion, while strong with them, is lacking without high buff support so we’re trying out an increase to the sentry damage on it.	”
	~ Ninja Kiwi

• Engineer Monkey base cost reduced from $400 to $350
• Sentries now spawn within 20% of their range to the track
• Sentry Champion sentry plasma damage increased from 2 to 3
• Cleansing Foam cost increased from $850 to $900
• Overclock's foam pierce increased from 10 to 15. Does not affect Ultraboost's foam pierce (30).
• Double Gun cost reduced from $500 to $450
• Bloon Trap cost increased from $3500 to $3600

Bug Fixes and General Changes

12.1

• Larger Service Area now increases Sentry deploy range (Arguably a nerf).
• Fixed a bug where unupgraded Engineers gained the Deconstruction buff.
• Fixed a bug where Bloon Trap granted camo detection and lead poppage to sentries.
• Engineer Monkey Knowledge prerequisites have been fixed.

13.0

• x-x-4 Bloon Trap no longer collects for reduced cash when under a Monkey Town.
• Acquisition range is correctly blocked by obstacles on High Finance.
• xx4 Bloon Trap should collect for the correct amounts after resuming save.
• x-x-4 Bloon Trap will no longer allow bonus traps to be placed when reloading save.

16.0

• x-4-x Overclock can now be targeted by Techbot.
• x-5-x Ultraboost will no longer trigger while techbotted if no target was previously set.

17.0

• 1-x-x Sentry Gun sentries no longer gain camo detection when a save is loaded.
• 1-x-x Sentry Gun sentry placement will no longer ignore 'smart placement' if the Engineer cannot reach the track.

20.0

• 5-x-x Sentry Champion should no longer cause a secondary explosion when manually sold.
• x-x-4 Bloon Trap, resolved collection sometimes displaying less cash than it should.

23.0

• 5xx Paragon Sentry "can always sell" property on sentries has been fixed to work in challenges as well.

24.0

• x-2-x Deconstruction description has been updated with more detail.
• x-4-x Overclock description has been updated with more detail.
• x-5-x Ultraboost description has been updated with more detail.
• x-x-1 Oversize Nails description has been updated with more detail.

30.0

• Resolved a save loading bug that could cause Foam to target the center of the map from any location
• [visual] x3x Cleansing Foam should now count damage when popping lead bloons

36.0

• 205 XXXL Trap now properly reduces the cooldown of new Bloon Traps.

38.0

• Resolved a crash that could occur when trapping a fortified blimp with a 025 trap after upgrading the parent XXXL trap into a paragon
• Engineer Paragon sentries are now correctly destroyed if their platform is removed
• Engineer Paragon sentries no longer position incorrectly when placed as the round ends
• Engineer Paragon no longer defaults to throwing out a Green Sentry after loading a save

Gallery

The engineer in the Monkey Knowledge screen in BTD 6

The Engineer as seen in the victory screen of Co-op Mode in BTD6.

All the upgrades unlocked in BTD6

In-game card

Lots of BTD6 Engineers

Engineer influenced by three Monkey Village buffs

Promotional Art, also including Elizi's alternative skin and the two new maps.

Not how sentries work

Entire Engineer Monkey Upgrade Tree for Bloons TD 6, including Master Builder

Engineer Monkey ready to be unlocked

All Tier 5 Engineers next to each other

Teasers

BTD6 Engineer Teaser 1 (released on Reddit)

BTD6 Engineer Teaser 2 (released on Facebook and Twitter)

Official artwork

Engineer Monkey official artwork since Version 12.0

Pre-12.0 official artwork of the Engineer Monkey

Instamonkey icon

Trivia

• The Bloon Trap and XXXL trap do not share points with other players in multiplayer, effectively siphoning money everyone else, particularly when place near the entrance.
• The engineer appears as the icon for Support towers in the Monkey Knowledge screen in BTD6 meaning it was most likely intended to be a launch tower but was not finished in the time frame they wanted to release the game in.
  • The engineer was eventually released in the 12.0 update with a different artwork than the Monkey Knowledge icon.
• In BTD6, this was the only tower where all of its tier 2 upgrades cost less than its tier 1 upgrades.
  • This is no longer true as of the 21.0 update, since Deconstruction now costs more than Larger Service Area.
• Sentries inside the range of a Monkey Village will have the effects of it, regardless of whether the Engineer that spawned them is inside the range of the Monkey Village.
• Overclock is the only Tier 4 Engineer Monkey to lack any form of eyewear. Sentry Expert wears experimental goggles, while Bloon Trap wears a pair of yellow tinted sunglasses.
• Sentry Champion formerly had the name 'Sentry Paragon', but was renamed to avoid confusion with the later added Paragons.
• According to Ninja Kiwi's October 29th 2021 blog, Engineer Monkeys trying to hit Paragon Sentries (referred as "sentry champion [sic]" in the blog) to speed them up causes these sentries to explode. Since then, Engineer Monkeys never hit their sentries ever again. Because hitting sentries to speed them up is a Team Fortress 2 reference, it can be implied that Engineer Monkeys use wrenches to hit their sentries.
• Each Engineer Monkey path corresponds roughly to a different engineering discipline. Path 1 themes around systems engineering, which involves designing and managing complex systems. Path 2 themes around chemical engineering, which involves implementing and optimizing processes in systems. Path 3 themes around mechanical engineering, which involves designing and creating mechanical systems.
• The Engineer's Bloon Trap and XXXL Trap upgrades are references to the ghost trap from Ghostbusters.
• As for Version 41.3, it is the only tower released after BTD6's initial launch to have a Paragon.
  • It is also the only tower released after BTD6's initial launch (not including Heroes) to recieve it's own pet as of upcoming 42.0 update.
• According to Ninja Kiwi's 12th July 2024 blog, there is a monkey celebrity called Nailer Swift, a singer and musician who makes songs about engineering and building turrets.