Strategy:CHIMPS

This article was last updated for: version 51.2

CHIMPS icon

CHIMPS is arguably the most difficult game mode in BTD6, especially if Powers are used in other game modes.

For purposes of clarity, the following definitions will be made for this article:

• Early-game = Rounds 6-40
• Mid-game = Rounds 41-80
• Late-game = Rounds 81-100

General recommendations

Preparation

• When playing CHIMPS on difficult maps, create a plan for each stage of the game based on what you currently know. It may help to observe how experienced players complete CHIMPS, so you can attempt to incorporate elements of their gameplay into yours without directly copying them. Learning how to create your own solution will improve your skills and prospects for future runs.
• While attempting to incorporate new strategies into harder maps or the first CHIMPS run without guides, doing some practice runs where retrying last round can be used freely is good practice that can build on the player's ability to defeat CHIMPS on their own. For maps where all parts of the game are difficult, get through the whole CHIMPS game with a red badge before going for a Black Border.
• Experiment different strategies in Sandbox or Challenge Editor to speed up the testing process if only a few rounds are being the roadblock. Make sure to turn off Monkey Knowledge before testing.
• Remember the rounds that frequently become a roadblock, and plan ahead for those rounds later on. Rounds that are challenging to nearly all CHIMPS runs are listed below.

The most challenging rounds

Round #	Bloons spawned	Reasoning
40	MOAB ×1	The MOAB is the hardest challenge of the early game. Without the entire early-game setup being prepared to deal good single-target damage and clean up the tight, high-RBE ceramics, this round could very easily be a dead-end.
63	Lead ×75 Ceramic ×122	This infamous round has 3 tight Ceramic waves with 40, 40, and 42 Ceramics respectively. One ability cannot handle all 3 waves, so the inability to sell and rebuy for cooldowns amplifies this round's difficulty. Towers that excel in grouped damage are required to beat this round.
75	Lead ×14 Fortified Lead ×14 Fortified MOAB ×3 BFB ×6	The 6 BFBs in 3 separate packs, especially the last dense pack of 3 BFBs, the fortified MOABs, and the Leads blocking many projectiles can stumble many strategies that cannot deal both strong single-target damage and solid grouped popping power.
78	Rainbow ×150 Ceramic ×75 BFB ×1 Purple ×80 Camo Ceramic ×72	Without a solid Camo popping power or reliable decamo, the densely packed Camo Ceramics will simply pass through unscathed.
90	Fortified Camo Regrow Lead ×500 DDT ×3	The 3 DDTs can easily catch new CHIMPS players off-guard, due to them being fast-moving blimps as opposed to slow-moving ones with Super Ceramics as the main threat. They brick a run entirely if no towers that can pop Camo, Black, and Lead have been placed before-hand.
95	Fortified Camo Regrow Lead ×500 Camo Regrow Purple ×250 Fortified MOAB ×50 DDT ×30	The extreme amount of DDTs on this round is a monumental challenge to many strategies, making many runs a dead-end. The Fortified MOABs and their Super Ceramic insides consume the pierce of projectiles that would have damaged the DDTs, posing further challenges.
98	Fortified BFB ×30 ZOMG ×8	This round has the highest RBE out of any round in pre-Freeplay CHIMPS. The high health of the fortified BFBs and ZOMGs, but especially the absurd amount of Super Ceramics (including Fortified) that they contain, make this round easily a dead-end.
99	MOAB ×60 Fortified DDT ×9	Many strategies that beat 95 fail due to having grouped DDT damagers that fall as DDTs gain 2x health on this round. MOABs and their insides continue to consume pierce. Unlike 95, ability cooldowns are a severe issue, with DDTs spawning right after the notorious Round 98.
100	BAD ×1	Many strategies that revolve around stalling and/or grouped popping powers completely fail to Round 100 due to the BAD being immune to all slowdowns from towers and requiring single-target damage options to be dealt with.

For a full list of rounds to be prepared for, including situationally difficult ones, see Strategy:Bloons TD 6. Many additional tips there for general gameplay can be used for CHIMPS as well.

Gameplay

• In the early-game and mid-game, attempt to place down towers that can be upgraded into solid options later on. Attempt to not place towers that cannot upgrade into anything that does not become wasteful once Super Ceramics come on Round 81.
• Always recognize the importance of support. They include Jungle Drums, Berserker Brew, Giant Condor, MOAB Glue, Relentless Glue, Bloon Sabotage, MOAB Press, Symphonic Resonance, and more. They tremendously assist the main damage tower in many cases for relatively little cost.
• Use good save-up towers for the mid-game that allows for the accumulation of money for a strong tower well-suited for the late-game and prevent the dropping of many towers that become redundant past Round 80. These save-up towers include Dragon's Breath, Bloon Area Denial System, Destroyer, Plasma Accelerator, and Aircraft Carrier.
• Do not spam towers whenever feeling like doing so and leave them at low tiers into the late-game. Focus on a few, strong towers with support centered around them to have the best prospects late-game. The exceptions to this rule are the few good, spammable strategies, such as Perma-Brew with many Destroyers, Sun Avatars, or a Sniper Monkey army. These strong, powerful, and relatively expensive towers, along with powerful heroes and exceptional supporting towers, are termed as win conditions and listed below.

Win conditions suited for most maps

Name	Portrait	Reasoning & how to use
Perma-Spike		Perma-Spike is extremely versatile on maps of all difficulty, and it is one of the few beginner-friendly options that does not fall off terribly on Expert maps. It tanks tremendous amounts of leaks that can easily occur with many strategies, and effectively guarantees victory in most runs. Use the 1-0-5 crosspath, and give it a Jungle Drums village and 3-0-1 Berserker Brew (which in combination give it over 40% more tanking power). On multi-lane maps where the lanes are distant enough to prevent Perma-Spike from reaching all lanes at once, its power somewhat falls off, but can still be used in a more complicated manner with Support Chinook. Combine it with towers that have solid grouped popping power, such as Glaive Lord, to reduce its stress under high-RBE rounds such as Round 98.
Glaive Lord		Glaive Lord, unlike almost all other towers, is both a relatively simple win condition on Beginner maps and a solid option on Expert maps. On easier maps, bends allow the rotating glaive to shine (with the ricocheting glaives also contributing significantly), while on harder maps, the long distance between tracks allow the ricocheting glaives to deal massive damage while repeatedly bouncing all over the map. Generally, Glaive Lord is best placed near a bend, where its rotating glaives perform the best, but it can still prove powerful without bends when placed near the track, thanks to its ricocheting glaives. Use 5-2-0 if other towers also need de-leading or MIB and use 5-0-2 if de-leading and MIB are not needed for anything else.
Obyn		Obyn is a simple yet versatile Hero, being useful throughout the course of the game on nearly all maps. His seeking attack performs well against the first rounds, and brambles deals with early-game Camos (albeit needing luck on multi-lane maps) and Round 40. Nature's Ward Totem provides valuable support throughout the game, and Wall of Trees tanks large amounts of leaks, especially at Level 20, at which it serves a similar role as Perma-Spike. Obyn's buffs to Magic towers are useful as well, especially to Druid of the Storm, Avatar of Wrath, and Archmage, with the latter two also having their weaknesses covered by Wall of Trees. Nonetheless, he remains a strong addition to strategies without Magic towers, thanks to his other utilities.
Ezili		Ezili's MOAB Hex ability is an exceptionally powerful asset, being able to eliminate heaps of blimps and reduce RBE stress on other towers throughout the mid-game and late-game. While her early-game is sub-par, she is capable of easily breaking open the Round 40 MOAB and future blimps thanks to Level 6. MOAB Hex is useful on all maps, and it synergizes the best with towers that deal solid overall damage but struggle to clumped Super Ceramics, such as Archmage and Prince of Darkness (which also benefits from Ezili's pierce buff to Zombie Bloons). The Level 20 MOAB Hex's ability to one-shot the BAD can be used for Expert maps, where it costs $13-16k to purchase and is cheaper than other options (such as First Strike Capability).
Corvus		After the version 44.0 buffs, Corvus reaches Level 20 with much fewer need for Nourishment micro, especially on harder maps, simplifying gameplay with him. He trivializes the early-game with Spear, simplifies Round 40 with Ancestral Might, saves up tremendous amounts of money with Trample for dense rounds and Repel and Frostbound and Ancestral Might for blimps in the mid-game, and is powerful in the late-game with Ancestral Might and Overload. As with Geraldo, it takes time to learn him, but it is worth it due to his versatility coming from his spellbook working with a wide variety of strategies and carrying his strength across nearly all maps. Place him at the start of the track so that he can constantly farm mana, and move him there with Spirit Walk if needed.
Silas		He is very effective with an Ice-focused strategy, breezing through the mid-game and late-game (except BADs) with Ice Monkeys, though his early-game can be difficult to master because of frozen immunities blocking many towers. He removes Ice Monkey's biggest weaknesses, ice fragments improve damage consistency, Ice Walls give more time to pop Bloons, and himself benefits from extra Frozen damage, with a large power spike once he unlocks Frozen Burial and its on-demand global freeze. On water maps, he allows land towers to be placed in more optimal locations. Icicles is his best mid-game carry, and Absolute Zero for late-game (and can receive his level 13 discount). His only weakness is a complete lack of BAD damage, which is compensated with single-target options such as MOAB Eliminator and Spike Storm.
Comanche Commander		Comanche does both solid damage and some support with its shoving capabilities. It especially shines on single-lane, alternating maps such as Bazaar, where many towers fall off. Compared to its competitor, Apache Prime, Comanche's lower price, greatly improved performance against DDTs, slight support with its shoves, and smaller susceptibility to chasing puts it on top despite being weaker against dense rounds. Use Geraldo and Glue Storm, as the former covers its weakness against dense rounds with Sharpening Stone, Genie Bottle, and Blade Trap, while the latter gives powerful debuffs, puts solid slowdown on Super Ceramics, and grants Comanche DDT popping power. Use the 2-0-5 crosspath, as Quad Darts greatly improves Comanche's damage and Pursuit is a good quality-of-life upgrade.
Carrier Flagship		Flagship wipes the floor with the entire mid-game and early late-game, saving up titanic amounts of money while retaining strong powers into the 90s. On water maps, its 17% buff to water towers becomes a strong utility. Use 5-2-0 if the Destroyer attack can be taken advantage of, and use 5-0-2 if not. Use Admiral Brickell, whose Naval Tactics and Mega Mine abilities both help greatly.
The Bloon Solver		Solver is arguably the best win condition against clumped low-tier blimps and clumped Super Ceramics, both of which are very challenging to CHIMPS runs. It wipes out Super Ceramics with ease, with its puddles triggering a chain effect that deals solid damage to blimps and other Super Ceramics as well. Pair it with Carpet of Spikes, which pops high-health blimps and DDTs to allow Solver to trigger the chain effect. Contrary to popular belief and the case in the past, 5-2-0 is the optimal crosspath for Solver, because the immense pierce is what make Solver a solid cleanup option in CHIMPS.
Bloon Exclusion Zone		When using the 2-0-5 crosspath with Camo detection, Stronger Stimulant, and Lead popping, BEZ clears the late-game with absolute ease on most maps. The high cost of BEZ can make its save-up intimidating, but when given Berserker Brew and Camo detection with the 2-0-4 crosspath, Bloon Area Denial System is a solid Tier 4 that easily saves up to BEZ with the help of a few solid mid-game towers, such as Dragon's Breath.
Pop and Awe		When paired with stuns such as Relentless Glue, Super Glue, and Striker Jones's Concussive Shell ability, Pop and Awe wipes out almost all rounds with ease. If needed, retarget occasionally to catch leaking Bloons and clumps of blimps that get far. Striker Jones, with his various buffs to Mortars, Concussive Shell stuns, Artillery Command ability resetting Pop and Awe's ability and granting it double damage at Level 20, and Target Command ability easing micro, is the best hero for Pop and Awe. Perma-Spike complements it well, covering its slight weakness against DDTs and catching any leaks that micro mishaps create. In addition, solid BAD damage options, such as Spike Storm or MOAB Eliminator, should be obtained to cover Pop and Awe's BAD weakness.
Super Glue		Super Glue, ever since its v41.0 buff to its splats, is an extremely effective stalling tower on almost all maps. It stuns massive amounts of Bloons and blimps at once with its splats, and is an overall stronger alternative to Icicle Impale, which is a decent stalling tower in its own right. It pairs especially well with Sauda and Pop and Awe, both dealing massively increased damage to Bloons and blimps stunned by Super Glue.
Pirate Lord		Pirate Lord is beginner-friendly, and does good damage in the latter part of late-game and early late-game. It starts to fall off in the 90s due to its relatively low single-target damage that resulted to the nerf to Cannon Ship's frags, but remains quite powerful due to its ability. Pair it with Admiral Brickell for her Naval Tactics and Mega Mines abilities.
Sky Shredder		Sky Shredder, being a global-range tower, is unimpeded by line-of-sight blockers on many difficult maps, thus it retains its power on practically all maps, from Beginner to Expert. Its missiles do good damage to the outer layers of high-health blimps, and its darts deal solid grouped damage to the insides. Sky Shredder fits well within a wide variety of strategies, and cleanup towers such as Perma-Spike pair especially well with it, as they tank the leaks that its somewhat unreliable darts can leave. Stronger Stimulant maximizes its damage.
Orca		Orca is one of the strongest win conditions for its cost. At Power 64, it one-shots ZOMGs and DDTs and deals massive damage to everything else surrounding it with its thrash. It wipes out the vast majority of most rounds, especially when paired with Overclock, which has full uptime on it thanks to it being a Tier 4 tower. Set it on Strong so that it gets the most amount of thrash time, switch to First if a line of Bloons/blimps are to its front, and reposition it if many Bloons/blimps exit its range. The best way to obtain a Power 64 Orca is to get two Power 24 Great Whites (which are far more efficient than additional Orcas) for the mid-game for a smooth save-up, and then merging them into Orca on Round 80. Orca's tendency to leak stray Bloons can be solved by cleanup towers such as Perma-Spike and Prince of Darkness.
Avatar of Wrath		On most maps, Avatar of Wrath can effectively wipe out most rounds in the late-game. Generally, the 0-1-5 crosspath with 5 Poplusts and a Stronger Stimulant maximizes its power. The best heroes for Avatar of Wrath are Geraldo and Obyn, with both granting solid buffs and Geraldo's Gerry's Fire being buffed by Poplusts. For DDT rounds, use MIB, Embrittlement, or Glue Storm. Perma-Spike pairs well with Avatar of Wrath, due to the latter struggling against DDT rounds and the end of rounds (with few Bloons on the screen) and Perma-Spike being well-suited for these situations.
Bomb Blitz		If it can be afforded before difficult rounds, Bomb Blitz can act as a safety cushion with its passive ability, in case of accidental leaks, for a low cost compared to most Tier 5's. The main attack is decent for cleanup, especially with Striker Jones allowing an ability reset and important buffs for all Bomb Shooters.

Towers not suited for CHIMPS

Name	Portrait	Reasoning
Rubber to Gold		Despite its bloon property debuffs, it is far too slow and inconsistent versus DDTs, and only marginally cheaper than Monkey Intelligence Bureau. Embrittlement is a far more effective choice against DDTs, and has better group-popping against all rounds, including dense Ceramic rounds such as Round 63.
Bloon Master Alchemist		When converting blimps into Reds, all money is lost from these blimps except for the <1% of its income that comes from the measly Red Bloon, making BMA lose upwards of $9,000 on rounds such as 98. BMA is also absolutely horrendous against DDTs. XXXL Trap does what BMA does but much better in every way while not losing money.
Benjamin		Benjamin's primary use is making cash which is not allowed. With Biohack being a worse Pat Rallying Roar, his only niche is downgrading difficult waves with Syphon Funding. Syphon is relatively difficult to use properly, so he should not be used by inexperienced players. Note that losses from Trojan can be avoided by placing Benjamin behind a Line of Sight blocker, which is not present on some maps.
Trade Empire		While Trade Empire does benefit other Merchantmen with bonus damage, it is primarily used for its income generation and as such should not be used seriously.
Monkey City		There is no income generation in CHIMPS, so Monkey City does nothing besides providing a free dart monkey every round and a minor range increase to itself. Purchasing it requires its preceding upgrade, Monkey Town, which costs $10,800 while doing absolutely nothing, and the amount of free Dart Monkeys gained throughout the game cannot feasibly save more money. For such a steep price, it is never used in a serious CHIMPS run.

Early game (rounds 6-40)

• Rounds 6-8 revolve around the starting combinations of towers. After those rounds, save up for upgrades, more towers, or the selected hero.
  • For most maps, the first few rounds can be completed with three 0-0-0 Dart Monkeys, with at least one on Strong.
  • Dart + Sniper works well on maps where a lack of range is a problem. Sniper on Strong to chip the Greens, and Dart to clean up.
  • Maps containing water can use Dart + Sub, Dart on Strong to chip away the Greens, and Sub to clean up the remaining bloons.
  • Dart + Engineer can be used similarly to three 0-0-0 Darts, the main difference is that Engineer is more "concentrated" damage than two Darts.
  • Certain maps (e.g. Water Park, Infernal) may support a Boomerang start, usually 0-1-1 into 0-1-2.
  • All Beginner Maps and most Intermediate Maps, and several Advanced and Expert Maps, can support a hero start. Quincy or Sauda are the best choices to beat first few rounds. Sauda is generally easier to start, while Quincy is more versatile because of his decent range.
  • Specific map formats may support other starting combinations. For example, the middle barrel of Spillway offers a reliable Ninja start into 1-0-0 and 1-0-1.
  • If not starting with a hero, save up for one as early as possible by only barely getting enough defense for rounds 6-8.
  • 0-0-0 Desperado can eliminate the need for extremely precise placement required on certain Expert maps. Two 0-0-0 Desperados notably can beat the first rounds of Quad and Bloody Puddles, with some targeting changes necessary on harder maps.
• By the start of the middle part of the early game (Rounds 15-30), the hero should have been obtained, unless it is Churchill or the map is a True Expert. Stronger towers are needed to defeat those rounds, so save ups become important.
  • Watch out for certain rounds with Bloon types that no towers on the screen can deal with, especially Round 24's Camo Green and Round 28's Leads.
  • Airburst Darts is a solid option on almost all water-containing maps. 2-0-2 crosspath is typically the go-to with Airburst, to hit bloons sooner, but even a non-crosspathed Airburst is beneficial.
  • Power 6 Barracuda completely wipes out all early-game Bloons passing through its radius, except for Camos and Leads.
  • Power 6 Adasaurus likewise wipes out the entire early-game, with the upside of Lead popping and the downside of smaller range.
  • Druid of the Jungle is arguably the best option on single-lane-per-round maps, but falls off when Bloons come from multiple entrances per round.
  • 1-2-0 Wall of Fire works on intersections, but be careful about the initial cooldown at the start of each round, and Round 25's Purples.
  • 0-0-0 or 1-0-0 Spike Factories can tank leaking Bloons well, in addition to fending off Camos in the early-game.
  • All of these towers carry their power well into the latter part of early-game, which is why they are generally recommended.
• The latter part of the early game, Rounds 31-40, contains the toughest rounds. In particular, the MOAB poses severe challenge to practically all unplanned early game setups. Obtain strong towers that can defeat those rounds and carry power into the mid-game, and do not spam low-tier defenses that do not upgrade into anything useful.
  • Destroyer does both solid MOAB damage and solid Bloon damage with the 3-1+-0 crosspath. Berserker Brew amplifies its power even further.
  • MOAB Mauler does well against Round 40, and retains power against grouped MOABs in the mid-game.
  • Give a Berserker Brew to the Airburst Darts and then upgrade it to Triple Guns. This setup cruises the 30s and early 40s with relative ease on most maps.
  • Dragon's Breath reliably pops all non-MOABs that pass through its wall of fire, excluding Purples. It remains powerful through the mid-game.

Mid-game (rounds 41-80)

• By the start of the mid-game, any reason to spam low-tier towers that do not upgrade to anything good vanishes. From now on, all towers obtained must either be or be upgradeable to towers that have strategic importance later on in the mid-game and/or in the late-game.
• Absolutely take advantage of the hero during the save-up. Use their abilities/inventories when needed, and they become worth upwards of ten thousand in the mid-game.
• In almost all cases, Berserker Brew/Stronger Stimulant should be purchased for the strongest mid-game tower(s). The damage, range, attack speed, and pierce buffs greatly enhance the power of almost all mid-game towers and allow them to save up much better.
• For rounds 41-60, focus on getting a mid-game carry. The mid-game carry tower would ideally carry its power throughout the entire mid-game and be able to save up large amounts of money for a win condition.
  • Bloon Area Denial System is solid on most maps and saves up to its tier 5, BEZ, fairly well.
  • Artillery Battery deals solid overall damage, especially on maps with loops such as Dark Path and Moon Landing and with ability usage on tougher rounds.
  • Comanche Defense is very solid on maps with one lane per round.
  • Plasma Accelerator deals solid MOAB-class damage and cleans up pre-Super Ceramic Bloons fairly well. Place it so that it has a long-straight line to shoot down on, and focus its high-damage point on the most dangerous clump of Bloons/blimps.
• During Rounds 61-80, a win condition that carries power into the late-game would ideally be obtained. At this point, attempt to not place down anything that becomes useless past Round 80. If no win conditions are obtained by Round 81, Super Ceramics that start appearing on that round could pose a massive problem. If the win condition is expensive (>$70,000 in total) and mid-game towers that do okay against Super Ceramics are present, obtain it in the early 80s.
  • Watch out for Rounds 63, 75, and 78, the hardest mid-game rounds. Make sure to have solid grouped popping powers for these rounds.
  • If playing on a land-covered map (such as Cornfield) and a water-based win condition (such as Carrier Flagship, Pirate Lord, and Orca) is desired, Lord of the Abyss can be purchased in this part of the game to allow for their placement.
  • Carrier Flagship solos the mid-game with relative ease on most maps and remains powerful in the late-game.
  • Glaive Lord can be afforded in the 70s on most maps, and it is a very solid win condition that remains very strong in the late-game.
  • Spiked Mines tanks large amounts of Bloons with its increased spike pierce and explosions. It and its preceding upgrade, Spiked Balls, both perform the best when paired with Berserker Brew and carry power well into the late-game.

Late game (rounds 81+)

• Super Ceramics start appearing on Round 81, having 60 (120 for Fortified) health and only spawning one children. Thus, many towers fall off against them, such as Recursive Cluster, Ring of Fire, and Crossbow Master. For this reason, these towers are generally not recommended for CHIMPS on Expert maps.
• Rounds 81-85 are the last rounds that give 0.2x instead of 0.1x income, so a win condition should be purchased by these rounds.
• Support towers listed in the General Recommendations section are worth it to get in practically every situation. It is generally not needed to obtain all of them every game, but purchasing some of them greatly aids the defense and is much more cost-efficient than purchasing another win condition.
  • Always buy Jungle Drums. Costing only about $3,000 for a tower that boosts the attack speed of everything in range by ~17.6% when one makes about $180,000 by Round 100's end is unquestionably a terrific deal.
  • Giant Condor is especially useful on multi-lane maps, as it can move large amounts of blimps to the same lane and turn the map into effectively single-lane. On single-lane maps, it is still a powerful stalling option and can bring leaking blimps back to the front.
  • Berserker Brew and Stronger Stimulant provide extremely large boosts to almost all win conditions for their price, with the exception of those who attack extremely fast.
  • Relentless Glue stuns massive amounts of Bloons and blimps with its chain effect from splats. It pairs especially well with Sauda and Pop and Awe, and can be upgraded to the much more powerful Super Glue if desired.
  • MOAB Press stalls dense rounds, such as 96 and 98, very effectively. 2-0-4 crosspath is recommended for pushing back many more blimps at once.
  • Bloon Sabotage makes DDT rounds much easier by making them move at half speed. Note that it does not slow the insides of blimps that pop while the ability is active.
• Some support towers are only useful for some situations.
  • MIB is a good AFK option for DDTs, but Embrittlement and Glue Storm also remove Lead immunities and provide other utilities.
  • Overclock is very solid, but only for runs with a relatively expensive win condition that concentrates most of the defense's damage, such as Glaive Lord, Orca, and BEZ.
  • Shattering Shells is useful for setups that struggle specifically versus Round 98, removing the threat of Fortified Super Ceramics, but is often outclassed by 2-3 MOAB Presses, which helps for other rounds as well.
• In the 90s, if both win conditions are relatively cheap (<$100,000 in total), a 2nd win condition can be obtained. If doing so, make sure that the win conditions either have no weakness or cover each other's weaknesses well. For example, Pop and Awe and Perma-Spike are a good duo, as the Pop and Awe wipes out dense rounds with ease and Perma-Spike covers Pop and Awe's slight weakness against DDTs while tanking Bloons that leak due to micromanagement errors.
• Make sure to have a defense with solid grouped popping power for dense rounds such as 98 and solid DDT popping power for rounds like 95 and 99.
• If using ability-based towers, ability cooldowns become important in the 90s, as nearly every round can pose a challenge to defenses with all abilities on cooldown. Attempt to leave at least 1 useful ability without or nearly without cooldown at the start of every round.
  • Round 98 into 99 is the most important transition to consider for abilities.
• Do not forget about Round 100 and leave little money for single-target damage options. If the defense relies on stalling or grouped popping powers, the BAD could easily become a dead-end. Unless a very solid single-target win condition has been obtained, save enough money for either a Spike Storm or a First Strike, with the latter being able to one-shot the BAD insides if timed slightly after the BAD reaches its last damage phase.

Strategies for harder maps

Many Advanced and Expert maps have layouts or gimmicks that prevent many aforementioned strategies from working. The majority of Expert maps, in particular, require extremely precise placements to defeat the first few rounds. If information for precise early-game guides are available, reading these guides are strongly recommended before playing those maps.

For more information on the strategies of those maps, see the Strategy section on their pages. Notably difficult maps specifically for early-game include:

• Bloody Puddles
• Ravine
• Dark Dungeons
• Quad
• #Ouch
• Muddy Puddles
• X Factor