Gravity Well: Tower Stats, Upgrades, Tips: The Gravity Well in Blockade Brigade: 400 gold, pulls ground enemies into one held knot for your splash guns. Levels, research and FAQ.

Plain-text version for AI assistants: https://blockadebrigade.com/llms-page-towers-gravity_well.txt. Site guide: https://blockadebrigade.com/llms.txt

Utility Tower

Gravity Well

Pulls ground enemies into a tight cluster and holds them

400 goldGround onlyResearch 150000

The Gravity Well opens a whirlpool on the path that drags every ground enemy near it into one tight knot and holds it there: 2.2 seconds at level 1, 3.1 at level 10. Then it recharges and opens the next one. It barely hurts anything itself. Its job is to stack enemies up for your splash guns, and any Cluster Mortar or Missile Silo inside its range fires at the held group the moment a well opens. It costs 400 gold and cannot catch anything that flies.

Gravity Well
Build your own Gravity Well

Attributes Level 1, on the ground

Cost
400 gold to build
Unlock
150,000 XPXP to research it (main menu, Upgrades & Research)
Sell value
300 gold 75% of the gold spent on it; all of it back within 15 seconds of placing
Can hit
Ground
Crush
6
Wells
0.16/s
Range
7 3.5 tiles
Targets at once
every ground enemy in its well
Power
uses 18 when firing · 1 on standby Full power only while it has a target. Switch it off to free its power.
Neighbours
+15% damage, +10% fire rate eachSame-type towers on its four sides, up to four (+60% / +40%). Connected Gravity Wells need 25% less power.
Platforms
+8% damage, +0.5 range a level of heightSmall +1, Medium +2, Large +3, up to 3 stacked. Hills up to 15 (above 5 is rare).
Ground
Grass: −5% damageNo penalty on rock, or on a platform (it stands on steel, even over grass)
Level parts
Base: 1 green level light, plate 01
Research
3 items, 5 levels each250 / 750 / 2,000 / 6,000 / 15,000 XP a level, 72,000 XP for all. Crushing Pull, Faster Collapse, Event Horizon
Cards
Damage, Fire Rate, RangeEnd-of-wave cards: up to 5 of each a game, then Endless cards

Base numbers: no research, cards or neighbours. (+n) is the change from the level before.

How to use it

Feed your splash guns

Every enemy caught is packed into a knot a few steps long, so a Cluster Mortar blast, a Cannon shell or Acid splash lands on all of them at once. Build those guns where they can reach the spot the well opens.

Put a Cluster Mortar or Missile Silo in its range

While a well is open, every one of them standing inside the Gravity Well's range turns on the held group, out of its own range too, and fires the moment the well opens instead of waiting for its reload.

Line them up for a Railgun

A held knot on a straight stretch is a short queue the slug goes straight through.

It buys time

Enemies held in a well are not walking toward your base. Enemies walking in while it is open are caught too, and the ones already past its centre are dragged back.

Cover the sky

It catches ground enemies only. Flying enemies pass right over it, so keep guns that hit air nearby.

Build in rows, go high

Each Gravity Well on the four sides of another gives it +10% fire rate, so it recharges sooner (and +15% crush). Each level of hill or platform gives +0.5 range, which also widens the circle of guns it calls in.

Build it

Pick a level, research, end-of-wave cards and where it stands, and see what your Gravity Well ends up doing: how wide the well is, how long it holds, how long it takes to recharge and how much of the time a well is open. Share the build with a link.

How the configurer works it out (formula, card values, share-link format)

How the game adds it up

  • Damage: level base x (1 + neighbours x 0.15) x (1 + height x 0.08) x ground (0.95 on bare grass, else 1) x (1 + research %) x (1 + cards % + Endless %)
  • Fire rate: level base x (1 + neighbours x 0.1) x (1 + research %) x (1 + cards % + Endless %)
  • Range: level base + height x 0.5 + level base x (research % + cards % + Endless %)
  • Dps: damage x fire rate, one hit on one target, before splash, afflictions and armour
  • Rule: Every source multiplies damage and fire rate; cards and Endless cards of one stat add into one percent. Range percents are all of the levelled base, added.

End-of-wave cards

Each wave offers 3 cards. Up to 5 cards of each stat a game, then that stat comes only as grey Endless cards (a random amount in the range shown). Percent per card:

CardNormalCommonRareEpicLegendaryMythicalEndless
Damage2%5%10%15%25%35%1-5%
Fire Rate2%5%10%15%25%35%1-5%
Range2%5%10%15%25%35%1-5%

Research

Unlock: 150,000 XP; its upgrades: 72,000 XP for all.

  • Crushing Pull: +10% a level, 5 levels (+50%), 250, 750, 2,000, 6,000, 15,000 XP
  • Faster Collapse: +6% a level, 5 levels (+30%), 250, 750, 2,000, 6,000, 15,000 XP
  • Event Horizon: +6% a level, 5 levels (+30%), 250, 750, 2,000, 6,000, 15,000 XP

Where it stands

  • Each same-type neighbour on its four sides: +15% damage, +10% fire rate (up to 4).
  • Each level of height (hill + platforms): +8% damage, +0.5 range.
  • Bare grass: damage x0.95 (no penalty on rock, or on a platform: it stands on steel, even over grass). One tile is 2 range units.

This tower's own rule

  • A well pulls the ground enemies within 2.6, 2.72, 2.84, 2.96, 3.08, 3.2, 3.32, 3.44, 3.56, 3.68 of its centre (along the path) together and holds them 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1 s, crushing each for its damage a second (every 0.5 s). A pulled enemy cannot be pulled again for 3 s. Recharge between wells = 1 / fire rate.

Worked examples

Share-link format

A build is the page address + #build: + parts joined by ~, in any order; parts left out are 0 / none. Opening the link loads the build and scrolls here. Links shared from the page also carry ?utm_source=...&utm_medium=...&utm_campaign=tower_build&utm_content=... before the hash; they are optional.

  • l<N>: tower level 1..10
  • r.<stat>.<N>: research level 0..5 of a research item (damage, fire_rate, range_radius)
  • c.<stat>.<digits>: end-of-wave cards of one stat, one digit per card = its rarity (0 Normal, 1 Common, 2 Rare, 3 Epic, 4 Legendary, 5 Mythical); at most 5 a stat
  • e.<stat>.<amount>x<count>: Endless cards of one stat: count cards of +amount% (only once that stat has 5 cards)
  • n<N>: same-type neighbours touching it, 0..4
  • h<N>: height: hill + platform levels, 0..15
  • g: standing on bare grass (no platform)
  • s<N>: level of the Cold Snap over it, 0 = none (1..10)
  • sp0: that Cold Snap has no power (it cools nothing)
  • w<N>: water tiles beside it, 0..4 (sides not taken by neighbours)
  • k<N>: towers in its connected chain, itself included (at least neighbours + 1)
  • kw<N>: water tiles beside the whole chain

Every level

Base numbers: no research, cards, height or neighbours. Damage is the crush: what each held enemy takes every second while a well is open. Fire rate is how often it can open a well. Well radius is how far along the path, either side of its centre, it catches enemies. Range is how far from the tower it can open a well, and how far it calls in guns. Power is what it needs while it has a target.

LevelUpgradeTotal spentCrushWellsRangeWell radiusHoldsImmune afterPower
1build 40040060.16/s72.62.2s3.0s18
26201,02080.16/s7.32.722.3s3.0s22
39611,981100.17/s7.62.842.4s3.0s25
41,4893,470120.17/s7.92.962.5s3.0s29
52,3085,778140.18/s8.23.082.6s3.0s32
63,5789,356160.18/s8.53.22.7s3.0s36
75,54614,902180.18/s8.83.322.8s3.0s40
88,59723,499200.19/s9.13.442.9s3.0s43
913,32636,825220.19/s9.43.563.0s3.0s47
1020,65557,480240.2/s9.73.683.1s3.0s50

Levels 1-10Every level makes the well a little wider (2.6 to 3.68 either side of its centre), holds it a little longer (2.2 to 3.1 seconds) and recharges a little faster (a new well every 6.25 seconds at level 1, every 5.1 at level 10).

GoldLevel 2 costs 620 gold and level 10 alone 20,655. The upgrades hold longer and catch wider, but a second Gravity Well (480 gold) can hold a different stretch of path, or the same one while the first recharges.

Research

Research (main menu, Upgrades & Research) makes every Gravity Well you build stronger. Each item has 5 levels for 250, 750, 2,000, 6,000 and 15,000 XP (24,000 XP for all 5).

Crushing Pull

+10% crush damage a level, +50% at level 5. It does not hold the well open longer.

Faster Collapse

+6% recharge speed a level, +30% at level 5: wells open more often.

Event Horizon

+6% range a level, +30% at level 5: it can open wells further away and calls in guns from further away. The well itself stays the same size.

Height and ground

  • Each level of height: +8% damage and +0.5 range.
  • Hills: up to 15 levels on every map; above 5 is rare.
  • Platforms (small +1, medium +2, large +3) stack up to 3 high: up to 9 more levels, on flat ground or on a hill. Research unlocks the sizes and stacking.
  • Highest it can stand: 24 levels, +192% damage, +12 range.
  • On grass: −5% damage; no penalty on rock, or on a platform (it stands on steel, even over grass).

Gravity Well FAQ

What does the Gravity Well actually do?

When it is ready, it opens a well on the ground enemy it is aiming at. Every ground enemy on that path within 2.6 of the well's centre (level 1) is dragged into a tight knot on that spot and held there until the well closes, 2.2 seconds later at level 1. While they are held they take a light crush. Then the tower recharges and opens the next one.

Can the Gravity Well catch flying enemies?

No. It catches ground enemies only. A well only grabs enemies walking the same path it opened on, so a stretch of another path that passes close by is left alone.

What if a well has nothing to catch?

Then it opens nothing and tries again 0.5 seconds later, without waiting a whole recharge. It only recharges after a well it really opened.

Why does the same group not get caught again?

An enemy let go by a well cannot be caught by any well for 3 seconds. That stops two or more Gravity Wells from holding the same enemies forever. Build them to take turns on different groups, or on the same stretch one after another.

Can fast enemies or bosses walk out of a well?

No. The pull is added on top of an enemy's own walking speed, so even fast enemies stay put. A very big enemy, more than 2.5 times as strong as the average of the others it caught, is dragged at 45% of the pull, so it reaches the knot later, but it is still held. A Domeguard with its bubble up, and every enemy sheltering under it, cannot be pulled at all.

Does it do any damage?

Very little. Every held enemy takes its damage each second while the well is open, as a small crush hit every 0.5 seconds: about 12 to each held enemy per well at level 1. Damage research raises it. The real damage comes from the guns you build around it.

Which cards does the Gravity Well get?

Its end-of-wave cards are Hold Time (the well stays open longer, and crushes a little harder), Recharge (wells open more often) and Reach (more range). It never gets Deep Wound, Poison, Armor Damage or Shield Damage cards. Damage research does not hold the well longer: only Hold Time cards and levels do.

Which guns does it call in?

Every Cluster Mortar and Missile Silo standing inside the Gravity Well's range. While a well is open they shoot at the held group even if it is outside their own range, and each fires once straight away as the well opens. When the well closes they go back to their own targets. Other guns are not called in, but any in reach of the knot gain from it.

Why did my Gravity Well stop opening wells?

Either nothing it can catch is in range (fliers, or enemies still immune from a well), or it is short of power. It needs 18 power at level 1 and 50 at level 10, and an open well collapses the moment the tower loses power.

How much power does a Gravity Well use when it has nothing to shoot?

Only 1: with no target it stays on standby, lights and radar on. It uses its full power only while it has a target: 18 at level 1, 50 at level 10 (the tower panel says "uses N when firing, 1 on standby"). If the grid cannot give it that, it stays on standby too: it keeps tracking enemies but cannot fire (LOW POWER). The panel's Switch off button turns it off completely: it draws nothing and does nothing until you Switch on again, so you can choose which towers run when power is short.