Last updated: August 4, 2026.

The Wave 28 Meltdown That Shouldn’t Have Happened

Jake had it all. Level 4 Minigunner. Level 3 Accelerator. Level 2 Commander. His loadout was straight from the meta tier list. He’d watched the videos. He knew the placements.

Wave 28 hit. The Fallen Honor Guard spawned with 8,000 HP and a damage resistance aura. Jake’s Minigunner was melting it — 45 damage per shot, Commander buff active, DJ range covering the entire lane. But the Honor Guard had friends. Six fast enemies spawned on the left lane and sprinted past Jake’s single chokepoint defense. His Minigunner was locked on the boss. His Accelerator was still charging. His Commander was buffing a tower that was shooting the wrong target.

He leaked six enemies. Then seven. Then the boss. Game over.

Jake’s mistake wasn’t his towers. It wasn’t his placement. It was his upgrade path. He’d poured 9,000 coins into maxing one Minigunner while ignoring everything else. He had no secondary DPS to cover the side lane. His Commander was level 2 when it should have been level 3. His DJ was still level 1 because “the range buff is enough.” Every coin he’d earned had gone into one tower — and that one tower couldn’t be in two places at once.

TDS upgrade paths aren’t about spending coins. They’re about spending them in the right order so that when wave 28 throws multiple threats at you, you have multiple answers. This guide is the upgrade priority framework that turns Jake’s wipe into a clear.

How Tower Upgrades Actually Work in TDS

Every tower in TDS has 5-6 upgrade levels, each with a gold cost and a stat increase. Simple enough. But the upgrade system has hidden mechanics that most players don’t notice until they’re already dead.

The Upgrade Cost Curve

Tower upgrades follow a steep cost curve. Level 1 is cheap. Level 2 is moderate. Level 3 is a jump. Level 4 is expensive. Level 5 is a luxury tax.

Here’s the standard pattern using Minigunner as the baseline:

  • Level 1: 1,500 coins. Base stats. Barely functional.
  • Level 2: 800 coins (2,300 total). Modest DPS increase. Still not threatening.
  • Level 3: 1,800 coins (4,100 total). Major power spike. The tower becomes a real threat.
  • Level 4: 3,200 coins (7,300 total). Solid increase but declining efficiency per coin.
  • Level 5: 5,000 coins (12,300 total). Marginal gain for massive cost. Victory lap territory.

The cost curve isn’t linear. It’s exponential. A level 5 Minigunner costs more than three level 3 Minigunners. The question isn’t “can I afford it?” — it’s “does this give me more value than the alternatives?”

The Hidden Upgrade Mechanics

Three things happen when you upgrade a tower that the stat card doesn’t show.

First, targeting priority changes. A level 1 tower targets the first enemy in range. A level 3 tower often gains “strongest” targeting, switching its fire to the highest-HP enemy. This matters because a level 3 tower that’s shredding a 50-HP zombie while a 5,000-HP boss walks past is functionally useless. Upgrade timing matters — you want your tower to hit level 3 right before the first boss wave, not after.

Second, hidden detection upgrades. Some towers gain hidden detection at specific levels. Golden Scout gets it at level 2. Crook Boss gets it at level 3. If you’re relying on these towers for hidden coverage and leave them at level 1, wave 24’s hidden enemies walk right through. The upgrade level isn’t just about damage — it’s about unlocking mechanics.

Third, placement footprint changes. Some towers (Engineer, Turret) change their physical footprint at higher levels. A level 5 Engineer’s sentry nest takes up more space than a level 1 Engineer. If you placed the Engineer in a tight spot expecting it to stay small, you’re going to have placement conflicts when you upgrade.

The Three Tower Upgrade Failure Patterns

Every TDS player has died to these. The difference is whether you recognize them before they kill you.

Failure 1: The Single-Tower Tunnel Vision

You pick your best DPS tower and pour every coin into it. Level 2 by wave 8. Level 3 by wave 14. Level 4 by wave 22. You feel invincible — your one tower is a monster.

Then wave 25 hits with enemies on both lanes. Your monster tower clears one lane perfectly. The other lane walks straight to the exit. You have no backup. Your other towers are level 1 because you spent everything on the one.

The tell: If your main DPS tower accounts for more than 60% of your total tower cost by wave 20, you’re tunnel-visioning.

The fix: Cap single-tower investment at 40% of total spending. Once your main DPS hits level 3, force yourself to spend the next 2,000-3,000 coins on something else — supports, a secondary DPS, or a leak catcher. The hardest upgrade to make is the one that doesn’t make your damage number go up. That’s exactly the one that saves your run.

Failure 2: The Support Starvation Spiral

You’ve got the economy guide memorized. Farms to level 3 by wave 18. DPS towers placed and upgraded. You’ve got coins. But you skipped Commander because “the fire rate buff is only 25%.” You skipped DJ because “I don’t need range, my towers are close to the track.”

Your level 4 Minigunner deals 45 damage per shot. A level 4 Minigunner with Commander and DJ deals effectively 75-80 damage per shot. You’re leaving 40% of your tower’s power on the table because you cheaped out on supports.

The tell: If you have a level 4 DPS tower and your Commander is below level 2, you’re starving your supports.

The fix: Support upgrades should never lag more than 2 levels behind your main DPS. Commander level 2 costs 1,500 coins and gives every tower in its radius a permanent 35% fire rate boost. That’s roughly equivalent to adding a free level 2 Minigunner to your defense — without taking a placement slot. DJ level 2 costs 800 coins and increases the discount to 15%. If you’re spending 8,000 coins on DPS upgrades after placing DJ, that 15% discount saves you 1,200 coins. The support pays for itself through math.

Failure 3: The Upgrade Order Inversion

You place Commander on wave 8. Farm on wave 12. DJ on wave 15. Accelerator on wave 18. Your upgrade order is backwards — you’re buffing towers that don’t exist yet while your early-game defense is a level 1 Scout.

The Commander sits there buffing nothing. The Farm arrives too late to pay back before wave 30. The Accelerator shows up on wave 18 with no coins to upgrade it because you spent everything on supports that had nothing to support.

The tell: If your support towers are placed before your DPS towers, you’ve inverted the order.

The fix: The upgrade order is: Farm → DPS (level 1-2) → Support (level 1) → DPS (level 3) → Support (level 2-3) → DPS (level 4-5). Farm comes first because it generates the coins for everything else. DPS comes second because you need to survive. Supports come third because they amplify the DPS you already have. The formula is: earn coins, build a weapon, then make the weapon better. Never build the amplifier before the signal.

The Upgrade Priority Decision Framework

Every wave, you have coins. Every wave, you have options. Here’s the framework for picking the right one.

The Three-Question Filter

Before every upgrade, ask three questions. If the answer to any of them is “no,” don’t make the purchase.

Question 1: Does this upgrade solve a problem I’ll face in the next 5 waves?

A level 5 Minigunner upgrade solves the wave 35 boss problem. But if you’re on wave 22, the next 5 waves have fast enemies, hidden enemies, and maybe a mid-boss. A level 5 Minigunner doesn’t help with hidden enemies. A level 3 Crook Boss does. The upgrade that solves the next problem beats the upgrade that solves a later problem.

Question 2: Is this the most coin-efficient damage gain available right now?

Calculate the DPS-per-coin of every available upgrade. A level 3 Minigunner upgrade costs 1,800 coins for +14 DPS (0.0078 DPS/coin). A level 1 Commander costs 800 coins and gives +25% fire rate to all towers in radius — if you have two towers in range dealing 30 combined DPS, that’s +7.5 effective DPS (0.0094 DPS/coin). The Commander is more efficient. Run the numbers.

Question 3: Does this upgrade unlock a mechanic I need?

Hidden detection, stun immunity, targeting priority changes — these unlock at specific levels. A level 2 DJ has a bigger circle than level 1 and reaches your core towers. That’s not a damage increase, it’s a coverage unlock. Mechanics beat stats in TDS. A tower that can hit the right enemy is worth more than a tower that hits harder but hits the wrong target.

The Upgrade Priority Tier List

Not all upgrades are equal. Here’s the priority ranking for every coin you spend in a match.

S-Tier: Buy Immediately

  • Farm to level 2 (pays for itself in 4 waves, generates infinite value)
  • Main DPS to level 3 (the universal power spike)
  • Commander to level 2 (permanent fire rate buff that multiplies everything)
  • DJ to level 2 (15% discount applies to every future purchase)

A-Tier: Buy When Affordable

  • Second Farm to level 2 (doubles your income)
  • Main DPS to level 4 (necessary for wave 25+ HP scaling)
  • Support towers to level 3 (maximizes buff coverage and ability uptime)
  • Secondary DPS to level 1 (coverage for second lane or hidden enemies)

B-Tier: Buy With Surplus

  • Main DPS to level 5 (luxury upgrade, only after supports are maxed)
  • Third Farm to level 2-3 (Hardcore only, or if you’re swimming in coins)
  • Tertiary DPS to level 2 (backup leak catcher)

C-Tier: Almost Never Buy

  • Early DPS (Militant/Scout) above level 2 (these towers get sold by wave 25)
  • Any tower to level 5 before wave 30 (you’re paying for a victory lap before you’ve won)
  • Support towers to level 4-5 before DPS is maxed (amplifying nothing)

Optimal Upgrade Paths by Tower Type

Every tower type has a different upgrade curve. Here’s the optimal path for each category.

Single-Target DPS (Minigunner, Accelerator, Turret)

These are your boss-killers. Their job is to melt one big target at a time. The upgrade path is all about timing the power spikes to boss waves.

Minigunner path: Level 1 (wave 12) → Level 2 (wave 14) → Level 3 (wave 18, before first boss) → Level 4 (wave 24, before second boss) → Level 5 (wave 32+, only if supports are maxed).

The key insight: Minigunner level 3 on wave 18 gives you enough damage to handle the wave 20-22 boss. If you delay level 3 to wave 22, you’re fighting the boss with a level 2 tower that deals 44% less damage. That’s the difference between a clean kill and a leak.

Accelerator path: Level 1 (wave 15) → Level 2 (wave 18) → Level 3 (wave 24) → Level 4 (wave 30+). Accelerator level 5 is almost never worth it — the charge time reduction at level 3 is the real power spike, and level 4’s damage increase is modest for the cost.

Accelerator has a unique quirk: its charge-up mechanic means raw DPS numbers lie. A level 2 Accelerator that’s constantly firing at full charge outdamages a level 3 Accelerator that’s constantly switching targets and resetting its charge. The upgrade path for Accelerator is less about levels and more about placement — put it somewhere with long sightlines where it can lock onto one target and stay locked.

Turret path: Level 1 (wave 12) → Level 2 (wave 16) → Level 3 (wave 22) → Level 4 (wave 28). Turret has the most linear upgrade curve of any DPS tower — each level gives roughly the same percentage increase. That makes it the most forgiving tower to upgrade reactively. If you’re falling behind, Turret level 3 is always a safe purchase.

Splash/Crowd Control (Rocketeer, Demoman, Mortar)

These towers clear groups. Their upgrade path is about coverage and splash radius, not raw DPS.

Rocketeer path: Level 1 (wave 8) → Level 2 (wave 14) → Level 3 (wave 20). Rocketeer’s splash radius increases at level 2 and again at level 3, making it one of the few towers where the upgrade is more about area coverage than damage. A level 2 Rocketeer with an expanded splash radius can cover a U-turn corner that a level 1 Rocketeer can’t reach.

Demoman path: Level 1 (wave 8) → Level 2 (wave 12) → Level 3 (wave 18). Demoman’s level 3 gives it a massive damage spike against grouped enemies. The upgrade is worth it on maps with tight chokepoints (Crossroads, Harbor) and wasted on open maps where enemies spread out.

Mortar path: Level 1 (wave 10) → Level 2 (wave 16) → Level 3 (wave 22). Mortar is map-dependent. On multi-lane maps where enemies cluster at intersections, Mortar level 3 is one of the most coin-efficient upgrades in the game. On single-lane maps, Mortar is a waste of a slot.

Support Towers (Commander, DJ, Medic, Farm)

Support upgrades follow a different logic. You’re not buying damage. You’re buying amplification.

Commander path: Level 1 (wave 12-14) → Level 2 (wave 18-20) → Level 3 (wave 26-28). Commander level 2 is the breakpoint — it bumps the passive fire rate buff from 25% to 35% and reduces the ability cooldown. Commander level 3 gives the ability a massive burst window. The upgrade from level 2 to 3 costs 2,500 coins and gives you roughly 15 seconds of 50% fire rate boost every 40 seconds. With a level 4 Minigunner in range, that’s 8,000+ extra damage per ability use.

DJ path: Level 1 (wave 14-16) → Level 2 (wave 18-20) → Level 3 (wave 24-26). DJ level 2 is the efficiency breakpoint — the 15% discount saves you 900-1,500 coins over the course of a Fallen run. DJ level 3 extends the range circle to cover your entire defense setup. Until level 3, you’re making placement compromises to keep towers in DJ range. After level 3, you can place towers wherever they’re optimal and the DJ reaches them.

Farm path: Level 1 (wave 3-5) → Level 2 (wave 6-8) → Level 3 (wave 16-20). Never upgrade Farm to level 3 before wave 15. The 1,400-coin cost is too high relative to your early-game income, and you’ll be defenseless while the Farm pays itself back. Farm level 3 is a mid-game investment, not an early-game one.

Medic path: Level 1 (wave 15-18) → Level 2 (wave 22-25). Only in Hardcore mode or when running Engineer against stun-heavy enemies. Medic is a binary tower — either you need stun cleanse or you don’t. If you need it, level 2 is enough. Level 3 Medic is rarely worth the coins.

Level 5 vs Max Level: The Breakpoint Analysis

The most expensive upgrade in TDS is the one that doesn’t change the outcome. Here’s when level 5 is worth it and when it’s a trap.

When Level 5 Wins Games

  • Minigunner level 5 with full buff support. A level 5 Minigunner with Commander level 3 and DJ level 3 outputs roughly 120 effective DPS. A level 4 Minigunner with the same buffs outputs roughly 85 effective DPS. That 35 DPS gap is the difference between killing the Fallen King before it reaches the exit and leaking 2,000 HP worth of boss. In Hardcore mode, where every point of damage matters, Minigunner level 5 is a legitimate win condition.

  • Engineer level 5 in Hardcore. Engineer’s sentry cap increases at level 5, and the sentries gain HP. In Hardcore mode, where waves last longer and sentries take more damage, level 5 Engineer sustains DPS through the entire wave instead of losing sentries mid-fight. The upgrade is expensive but the alternative is losing your primary DPS source halfway through wave 35.

  • Turret level 5 on long maps. Turret’s linear scaling means level 5 is proportionally the same value as every other level. On maps with long sightlines (Crossroads, Harbor), Turret level 5 is a safe investment because it’ll fire at full effectiveness for the entire wave.

When Level 5 Is a Trap

  • Accelerator level 5. The charge time reduction at level 3 is the real power spike. Levels 4 and 5 give modest damage increases that don’t change Accelerator’s role or effectiveness. The 5,000-coin level 5 upgrade buys you roughly 15% more DPS. A level 1 Turret in the same spot costs 2,000 coins and adds 20+ DPS. The math doesn’t lie — place a new tower instead.

  • Any tower without buff support. Level 5’s value is multiplied by Commander and DJ. Without buffs, the raw DPS gain is underwhelming. A level 5 Minigunner with no supports deals 55 DPS. A level 4 Minigunner with Commander and DJ deals 85 effective DPS. The buffs are worth more than the level. Always max supports before buying level 5 on any tower.

  • Level 5 before wave 30. The opportunity cost is too high. Those 5,000 coins could be two level 1 meta towers, or a level 3 secondary DPS, or Commander level 3 plus DJ level 2. Level 5 is a wave 32+ purchase. Buying it earlier means you sacrificed mid-game coverage for late-game overkill — and you might not reach the late game.

The Level 5 Decision Rule

If you’re considering a level 5 upgrade, run this math: divide the upgrade cost by 2,000 (the cost of a level 1 meta DPS tower). That’s how many new towers you could place instead. If placing that many new towers would deal more than 50% of the level 5 DPS gain, place the new towers. Coverage beats concentration in TDS, and level 5 is the ultimate concentration play.

Mode-Specific Upgrade Priority

The upgrade framework changes based on game mode. Here’s what changes and why.

Normal Mode: The Sprint Economy

Normal Mode ends around wave 20. You don’t have time for compound returns. The upgrade priority is: one DPS tower to level 3 by wave 12, supports if you have spare coins, and nothing else matters.

  • Skip Farm entirely or place one Farm at level 1-2. The mode ends before level 3 Farm pays back.
  • One DPS tower (Minigunner or Turret) to level 3 by wave 12. That’s your entire win condition.
  • Commander level 1-2 if you have spare coins after wave 14. DJ is optional — the discount doesn’t have enough waves to pay back.
  • Do not place a second DPS tower. You don’t need coverage for 20 waves. One maxed tower clears Normal.

Fallen Mode: The Standard Framework

Fallen Mode is the baseline. The three-phase upgrade framework applies exactly as written. The only mode-specific note: Fallen’s wave 22-26 stretch is the hardest window in the game relative to your income. You need your main DPS at level 3-4 and your supports at level 2 by wave 22. If you’re behind on upgrades at wave 20, sell non-essential towers and catch up. Fallen doesn’t forgive late upgrades.

Golden Mode: The Crate-Weighted Economy

Golden Mode is structurally similar to Fallen but with a twist: clear speed affects crate drops. The upgrade priority is slightly different because you’re optimizing for speed, not just survival.

  • One Farm instead of two. The extra tower slot goes to a DPS or support that speeds up clears.
  • Upgrade DPS towers one wave earlier than you would in Fallen. The mode rewards aggression.
  • Commander ability timing matters more in Golden — sync it with crate-spawning waves for maximum efficiency.

Hardcore Mode: The Defense-First Inversion

Hardcore Mode flips the standard framework. Economy comes second. Survival comes first.

  • Waves 1-10: One DPS tower to level 2. One Farm to level 1. That’s it. You need damage to survive the early rush waves.
  • Waves 11-18: Second DPS tower to level 1-2. Farm to level 2. Commander level 1. This is the danger zone — enemies are tanky and your economy is still ramping.
  • Waves 19-25: DPS to level 3. DJ level 1. Second Farm to level 2. Supports to level 2. You’re catching up on economy while holding the line.
  • Waves 26-40: Max everything. DPS to level 4-5. Supports to level 3. Third Farm if you’re confident. The late game is where Hardcore’s economy pays off.

The key difference: in Hardcore, you upgrade DPS before Farm. In every other mode, you upgrade Farm before DPS. The mode punishes greed so hard that the mathematically correct play is the “wrong” one — you invest in damage first because dead players don’t collect Farm income.

Counter-Intuitive Insight 1: Upgrading the Wrong Tower Is Better Than Not Upgrading at All

This sounds insane. But hear me out.

A player who hesitates on wave 15 because they’re not sure whether to upgrade Farm or DPS — and does neither — loses more games than a player who picks the “wrong” upgrade. Coins sitting in your bank are coins that aren’t working. A level 2 Militant bought on wave 15 is a suboptimal purchase. But it deals damage. It contributes to wave clear. It buys you time.

A player with 2,000 unspent coins on wave 18 is functionally playing with a 2,000-coin handicap. The “wrong” upgrade at least does something. Paralysis does nothing.

The lesson: if you can’t decide between two upgrades in 10 seconds, flip a mental coin and pick one. The cost of indecision is higher than the cost of a suboptimal upgrade. You can recover from buying the wrong thing. You can’t recover from buying nothing.

Counter-Intuitive Insight 2: The Most Important Upgrade in the Game Costs 800 Coins

Commander level 1 costs 800 coins. It gives a 25% fire rate buff to all towers in its radius. That’s it. No damage. No range. No hidden detection.

But that 25% fire rate buff applies to every tower in range for the entire game. If you have three towers in Commander range dealing a combined 40 DPS, that 800-coin Commander is effectively adding 10 DPS — the equivalent of a level 1 Minigunner that costs 1,500 coins. And unlike the Minigunner, the Commander doesn’t take a placement slot that could hold a DPS tower. It sits in a corner and multiplies everything you’ve already built.

The most coin-efficient damage upgrade in TDS isn’t a DPS tower level. It’s Commander level 1. Players skip it because “it doesn’t do damage.” The damage tracker disagrees — it just shows the damage on the DPS towers, not the Commander that made it possible.

Counter-Intuitive Insight 3: Selling a Level 3 Tower to Afford a Level 1 Meta Tower Is a Net Win

Your level 3 Militant cost 2,850 coins. It deals 12 damage per shot. On wave 24, enemies have 300+ HP. The Militant needs 25 shots to kill one enemy. It’s a pea shooter.

Selling it returns 1,995 coins. A level 1 Accelerator costs 2,500 coins. You’re 505 coins short — one wave of Farm income.

The Accelerator deals 12 damage per shot but fires 4x faster than the Militant. It also gains damage as it charges. By the time the first boss arrives, the Accelerator is dealing 3-4x the Militant’s effective DPS for roughly the same net cost.

The 855-coin “loss” from selling the Militant is actually an investment that returns 300% in damage output. The math isn’t close. The emotional attachment to “my tower I’ve had since wave 5” is the only thing keeping the Militant on the field.

Counter-Intuitive Insight 4: DJ’s Discount Is More Valuable Than Its Range Buff

DJ’s range buff is flashy. You see the circle expand. You see your towers reaching further. It feels powerful.

DJ’s 10-15% upgrade discount is invisible. You don’t see the coins you saved. You don’t get a notification. But the math is undeniable.

Over a full Fallen Mode run, you’ll spend roughly 25,000-35,000 coins on upgrades. If DJ is placed by wave 14 and covers your main towers, that’s 20,000-28,000 coins spent inside DJ’s radius. At 15% discount (level 2 DJ), you save 3,000-4,200 coins. DJ costs 2,000 coins to place and upgrade to level 2. The discount alone generates 1,000-2,200 coins of net profit.

The range buff is free. The discount is the real economic engine. When you’re deciding between DJ level 2 and a DPS upgrade, remember: DJ level 2 is a DPS upgrade — it just delivers the damage through cheaper future purchases instead of immediate stats.

Counter-Intuitive Insight 5: The Best Upgrade Order Is the One That Makes You Uncomfortable

The natural instinct is to upgrade the tower that feels weakest. Your Militant is struggling on wave 18 — upgrade it. Your Farm is level 1 — upgrade it. Your Commander is sitting there doing nothing — leave it.

The correct upgrade order is the opposite. Upgrade the tower that enables everything else. Farm generates coins for future upgrades. Commander multiplies damage you’ve already built. DJ discounts purchases you haven’t made yet. These upgrades feel bad because they don’t immediately solve the problem in front of you. You’re upgrading Farm while enemies are leaking. You’re upgrading Commander while your DPS is falling behind.

But the player who upgrades Farm on wave 8 while enemies are a mild threat has 3,000 extra coins by wave 25. The player who upgrades Commander on wave 14 while their DPS is “good enough” has a 35% damage multiplier for the remaining 20 waves. The uncomfortable upgrade is the one that wins the game.

The Wave-by-Wave Upgrade Decision Tree

Here’s the exact upgrade decision tree for a standard Fallen Mode run. Follow it wave by wave. Deviate only when the map or enemy composition demands it.

Waves 1-5:

  • Place first Farm. Upgrade to level 1 (400 coins).
  • If enemies are leaking, place one Militant or Scout at level 1 (250-350 coins). Otherwise, save.
  • Goal: Farm level 1 placed by wave 4. 200-300 coins in bank.

Waves 6-10:

  • Upgrade Farm to level 2 (700 coins). This is non-negotiable. Do it before any DPS purchase.
  • Place Commander if affordable (800 coins). If not, place one Militant/Scout at level 1 for defense.
  • Goal: Farm level 2 by wave 8. Commander or DPS placed by wave 10. 300-500 coins in bank.

Waves 11-15:

  • Place second Farm. Upgrade to level 1 (400 coins).
  • Place DJ (1,200 coins). If not affordable, place main DPS tower (Minigunner/Accelerator/Turret) at level 1.
  • Upgrade main DPS to level 2.
  • Goal: Two Farms level 2. DJ level 1. Main DPS level 2. 500-800 coins in bank.

Waves 16-20:

  • Upgrade second Farm to level 2 (700 coins).
  • Upgrade main DPS to level 3 (1,800 coins). This is the power spike that handles the wave 20-22 boss.
  • Upgrade Commander to level 2 (1,500 coins).
  • Upgrade DJ to level 2 (800 coins).
  • Goal: Main DPS level 3. Commander level 2. DJ level 2. Two Farms level 2. 500-1,000 coins in bank.

Waves 21-25:

  • Upgrade both Farms to level 3 (1,400 coins each). Do this during wave 21-22 if your DPS is holding.
  • Upgrade main DPS to level 4 (3,200 coins). This handles the wave 25-28 enemies.
  • Place secondary DPS at level 1 (1,500-2,500 coins). This covers the second lane or hidden enemies.
  • Goal: Main DPS level 4. Two Farms level 3. Secondary DPS level 1. Supports level 2. 500-800 coins in bank.

Waves 26-30:

  • Upgrade Commander to level 3 (2,500 coins).
  • Upgrade DJ to level 3 (1,500 coins).
  • Upgrade secondary DPS to level 2-3.
  • Goal: Supports level 3. Secondary DPS level 2-3. Main DPS level 4. 500-1,000 coins in bank.

Waves 31-35:

  • Upgrade main DPS to level 5 if affordable and supports are maxed.
  • Otherwise, upgrade secondary DPS or place tertiary DPS for leak catching.
  • Goal: All towers maxed or close to it. Coins fully deployed. Win.

The Upgrade Cost Efficiency Table

For the number-crunchers. Here’s the DPS-per-coin efficiency for the most common upgrades.

Minigunner:

  • Level 1 to 2: 800 coins, +6 DPS. 0.0075 DPS/coin. Decent.
  • Level 2 to 3: 1,800 coins, +14 DPS. 0.0078 DPS/coin. Best value.
  • Level 3 to 4: 3,200 coins, +13 DPS. 0.0041 DPS/coin. Declining.
  • Level 4 to 5: 5,000 coins, +10 DPS. 0.0020 DPS/coin. Poor.

Accelerator (approximate, charge-dependent):

  • Level 1 to 2: 1,200 coins, +8 effective DPS. 0.0067 DPS/coin.
  • Level 2 to 3: 2,400 coins, +18 effective DPS. 0.0075 DPS/coin. Best value.
  • Level 3 to 4: 4,000 coins, +10 effective DPS. 0.0025 DPS/coin. Poor.

Turret:

  • Level 1 to 2: 1,000 coins, +8 DPS. 0.0080 DPS/coin. Solid.
  • Level 2 to 3: 2,000 coins, +12 DPS. 0.0060 DPS/coin. Good.
  • Level 3 to 4: 3,500 coins, +12 DPS. 0.0034 DPS/coin. Declining.

The pattern is clear: level 3 is the sweet spot for every DPS tower. Level 4 is necessary but inefficient. Level 5 is a luxury. Spend your coins accordingly.