First Last Line of Defense

First Last Line of Defense makes the first Spike Factory you buy each game $150 cheaper. It is a second-row Support knowledge that needs One More Spike, and it costs one Knowledge Point with no Monkey Money.

The discount is applied after the difficulty price change, so it is always a flat $150. The first Spike Factory costs $700 on Easy, $850 on Medium, $930 on Hard and $1,050 on Impoppable. Every later Spike Factory costs the normal $850, $1,000, $1,080 and $1,200.

How it changes the game

The discount only applies to the first Spike Factory you place, and only once. If you sell that factory, the next one is full price. So the knowledge is worth exactly $150 per game, and only in games where you use a Spike Factory.

Where that $150 matters is the opening. With More Cash from the Primary tree you start most games with $850, which on Medium is exactly enough for a discounted Spike Factory as your first tower. That lets you open with a factory on maps where it is the best early defence, or play Spike Factory first in challenges where other towers are banned.

Later in the game, $150 is irrelevant. A late Spike Factory that you add as a last line of defence for blimps (which is where the name comes from) is bought at a point where $150 means nothing.

One small catch: in strategies that sacrifice money, such as a Sun Temple or a Paragon, any first-tower discount slightly lowers the value of the towers you sacrifice. It is rarely enough to change a degree or tier, but be aware of it if you calculate exact thresholds.

Is it worth it?

Priority: situational. The effect is small, but the knowledge is cheap and it is the only way to reach Very Shreddy and then Hi-Value Mines, which cuts $1,500 off Spiked Mines. Players who like Spike Factory openers, Deflation or spike-based late game should take it early.

Compared with Vigilant Sentries, the other knowledge under One More Spike, it is the better pick if you use Spike Factories more than Engineers. Most players end up taking both because points are plentiful later.

Where it works

First Last Line of Defense is active in every mode with Monkey Knowledge enabled, including Impoppable and Half Cash. It is off in CHIMPS, where your first Spike Factory costs full price. Challenges with MK disabled and Rogue Legends also ignore it.

Frequently asked questions

How much is the first Spike Factory with First Last Line of Defense?

$700 on Easy, $850 on Medium, $930 on Hard and $1,050 on Impoppable.

Does the discount come back if I sell my first Spike Factory?

No. Only the first Spike Factory placed each game is discounted.

Can I open with a Spike Factory on Medium?

Yes, with More Cash you start with $850, which is exactly the discounted price.

What does First Last Line of Defense unlock?

Very Shreddy, which then leads to Hi-Value Mines.