Defence grid

Gun Tower
Gun tower
 * Level 1 gun tower - Total Cost: 100 DPS: 10 Range: 3.50 squares
 * Level 2 gun tower - Total Cost: 300 DPS: 30 Range: 3.75 squares
 * Level 3 gun tower - Total Cost: 700 DPS: 70 Range: 4.00 squares

Inferno Tower
Inferno tower
 * Level 1 inferno tower - Total Cost: 150 - DPS: 8.5 - Range: 2.50 squares - Cone: 70 degrees
 * Level 2 inferno tower - Total Cost: 450 - DPS: 23 - Range: 2.50 squares - Cone: 80 degrees
 * Level 3 inferno tower - Total Cost: 1050 - DPS: 48 - Range: 2.50 squares - Cone: 90 degrees

It's balanced so one yellow tower is the same as a line of 3 green laser towers spaced about 5-10 seconds apart, and one red is the same as 7 green towers spaced about 5-10 seconds apart.

Note that it's a little more complicated, because it depends on if two towers are hitting the same alien or not. With laser towers, they try to hit different things, so they stack linearly generally, unless there's only one guy going past.

Tesla Tower
Tesla Tower

Tesla towers cost 175, making them 1.75x more expensive than gun towers (by way of damage comparison - gun towers are the baseline).

A tesla tower is most effective when it charges up- the green tesla tower has 4 charge levels, and it takes 3 seconds per charge level. As soon as an enemy is in range, it discharges all of it's charges and starts charging up again.

Green tesla tower
The green tesla tower also chains to a second enemy, doing 2/3damage to it.


 * Charge level 0 (0-3 seconds) : doesn't fire
 * Charge level 1 (3-6 seconds) : 33 dmg (primary) + 22 dmg (2nd)
 * Charge level 2 (6-9 seconds) : 49 dmg (primary) + 33 dmg (2nd)
 * Charge level 3 (9-12 seconds) : 74 dmg (primary) + 49 dmg (2nd)
 * Charge level 4 (12+ seconds) : 111 dmg (primary) + 74 dmg (2nd)

As you can see, even if the tesla never has a chance to charge up and there are at least 2 enemies, it'll do 55 dmg every 3 seconds (18.3 dps for 175), making it slightly more damage than the gun tower, with a shorter range (and it can't hit flying mobs and is weaker against solo bosses when it can't double chain).

The tesla's range is 150 (2.5 squares), as compared to the gun's 210 (3.5 squares).

The real beauty of the tesla tower is when it charges up though. I like to put it near the 'edge' of the current front (where the aliens are getting to). On Flight Plan, for instance, since it's so short, I like them near the end.

Stats for the other levels of tesla tower:

Amber tesla tower

 * Base dmg: 58
 * 5 charge levels
 * 2.75 sec charge
 * Each charge level does 1.5x the damage
 * Chains twice, each chain does 2/3rds of the damage

Total Cost: 175 + 350 = 525
 * Charge level 0 (0-2.75) : doesn't fire
 * Charge level 1 (2.75-5.5) : 58 + 39 + 26
 * Charge level 2 (5.5-8.25) : 87 + 58 + 39
 * Charge level 3 (8.25-11) : 131 + 87 + 58
 * Charge level 4 (11-13.75) : 196 + 131 + 87
 * Charge level 5 (13.75+) : 294 + 196 + 131

Red tesla tower

 * Base dmg: 90
 * 6 charge levels
 * 2.5 sec charge
 * Each charge level does 1.5x the damage
 * Chains three times, each chain does 2/3rds of the damage

Total Cost: 175 + 350 + 700 = 1225
 * Charge level 0 (0-2.5) : doesn't fire
 * Charge level 1 (2.5-5) : 90 + 60 + 40 + 27
 * Charge level 2 (5-7.5) : 135 + 90 + 60 + 40
 * Charge level 3 (7.5-10) : 203 + 135 + 90 + 60
 * Charge level 4 (10-12.5): 301 + 203 + 135 + 90
 * Charge level 5 (12.5-15): 450 + 301 + 203 + 135
 * Charge level 6 (15+) : 675 + 450 + 301 + 203

Because you want time for them to charge up, the tesla tower doesn't scale as well with the temporal as the gun tower does, but it is a lot more efficient in the right circumstances.

Shields
There are two factors to consider when facing shields-

(1) Shields are immune to heat

Yeah, that's it - they are vulnerable to anything else.

The heat weapons are:


 * Laser - 100% heat (so 0% effective vs. shields)
 * Inferno - 50% heat (so 50% effective vs. shields)
 * Meteor - 20% heat (so 80% effective vs. shields)

The other 4 ground damage towers hit shields with 100% effectiveness:

Tesla, Gun, Cannon, Concussion

(2) When spires confer shields to nearby aliens, area of effect towers will only hit the shared shield once, rather than once for each alien.

This means that spires offer a sort of "AoE" protection. The concussion and inferno towers will not be nearly as effective against the group of aliens protected by the shield.