Néon Tower Defense: tower value for money and build order

The question this game really asks

Néon Tower Defense looks like a placement game, but it is first of all a budgeting problem. You get ten build slots spread around a single ten-point path, 2,800 pixels long, which every enemy follows from the top down to your base. You start with 120 money and 20 lives. Every enemy killed pays out: 6 for a normal enemy, 5 for a fast one, 14 for an armoured one.

There is no interest mechanic and no bonus for hoarding: money that sits idle produces nothing, and above all it produces no kills — so no income. The only question worth asking is therefore: for a given sum, which purchase removes the most enemy hit points per second? Everything else follows from that.

What a point of damage really costs

The in-game cards show damage and fire rate separately, which makes comparison hard. Multiply the two and you get damage per second; divide the price by that and you get the only figure that settles the argument. Here are the three towers freshly placed, at level 1.

Build cost, damage per second, and the price of one point of damage:

• Rapid tower — 40 money, 4 damage at a rate of 3.2 shots per second, so 12.8 damage per second. Price of a point: 3.13.
• Cannon — 80 money, 26 damage at a rate of 0.85, so 22.1 damage per second. Price of a point: 3.62.
• Frost tower — 60 money, 3 damage at a rate of 1.4, so 4.2 damage per second. Price of a point: 14.29.

The rapid tower is therefore the cheapest source of damage in the game, with the cannon close behind at a 16% premium per point. The frost tower costs more than four times as much for the same damage: it is not an attacking tower, and judging it on its damage makes no sense — we come back to it below.

A second tower almost always beats an upgrade

That follows directly from the previous point, and it is the most common early-game mistake. Upgrading your rapid tower to level 2 costs 45 and adds 8.8 damage per second: you are paying 5.11 a point. Placing a second rapid tower on a free slot costs 40 and adds 12.8 damage per second: you are paying 3.13 a point, for 5 money less.

The same arithmetic on the other upgrades returns the same verdict:

• Rapid, level 1 to 2 — 45 for 8.8 more damage per second, so 5.11 a point.
• Rapid, level 2 to 3 — 70 for 14.4 more, so 4.86 a point.
• Cannon, level 1 to 2 — 90 for 17.8 more, so 5.06 a point.
• Cannon, level 2 to 3 — 140 for 29.4 more, so 4.76 a point.

None of those upgrades comes in under 4.76, while a fresh build stays at 3.13 or 3.62. And the gap is in fact wider than those numbers say: a new tower occupies an unused slot, so it covers a stretch of path nothing was watching, whereas an upgrade adds damage where you were already shooting. As long as one of the ten slots is free, build.

The frost tower: essential, and never to be upgraded

The frost tower is not judged on its damage. With every shot it slows every enemy inside its range — not just its target — halving their speed for 900 milliseconds. Since it fires every 714 milliseconds, the effect is refreshed before it expires: an enemy crossing its zone stays slowed continuously.

An enemy moving at half speed spends twice as long under fire from every tower covering the same stretch of path. In other words, a frost tower doubles the effective damage of its neighbours. Its value for money is therefore worked out like this: it costs 60, and buying the same amount of damage in rapid towers would cost 3.13 a point. It comes out ahead as soon as the towers sharing its zone total roughly 20 damage per second — that is two rapid towers, or a single cannon.

Then comes the trap, and it is the most counter-intuitive advice in this guide. Upgrading a frost tower costs 70 then 110, and improves only its damage — from 4.2 to 12.6 per second — and its range, from 175 to 215 pixels. The slow itself does not change: halved speed and a duration of 900 milliseconds are fixed values of the game, identical at level 1 and at level 3.

Rapid or cannon: a question of wasted damage

On paper the rapid tower wins, at 3.13 a point against 3.62. But the damage-per-second figure assumes every shot is fully used, and that is not the case for a cannon early on. A cannon deals 26 damage a shot, when a normal enemy has 8 hit points on the first wave, 21 on the fifth and 27 on the sixth. Before wave 6, every shell therefore wastes most of its power, and the cannon’s theoretical 22.1 damage per second is never reached.

Fire rate makes it worse. A cannon fires every 1,176 milliseconds, a rapid tower every 313. Against fast enemies, which arrive on wave 3 and move 1.7 times quicker than the rest, a cannon will often only have time for two or three shots while they cross its zone. The rapid tower lands eight to ten in the same span.

The division of roles therefore settles itself:

• Rapid tower — the safe early bet, and the answer to fast enemies right to the end of the run.
• Cannon — needlessly expensive before wave 5, essential after it: armoured enemies arrive on wave 5 with 3.2 times the hit points of a normal one, so 69 when they first appear and 236 on wave 10.
• Frost tower — one per already-defended zone, never upgraded.

The recommended build order

Everything above adds up to a sequence, each step justified by the return available at that moment rather than by a stylistic preference.

With your starting 120 and then the income of the first waves:

1. Wave 1 — place three rapid towers, on three slots spread along the path. That is exactly 120, for 38.4 damage per second, where a cannon plus a rapid would cost the same for only 34.9, concentrated on two points.
2. Waves 2 to 4 — keep buying rapid towers every time you reach 40, upgrading nothing at all. Waves gain 2 enemies each and fast enemies appear from wave 3: coverage is what you need, not concentrated power.
3. Wave 5 — the armoured enemies arrive, and the wave’s total hit points double at a stroke, from 180 to 363. This is the moment for your first cannon: its 26 damage a shot are no longer wasted, and nothing else punches through armour properly.
4. Waves 6 to 8 — add a frost tower on the best-covered stretch, since you now have well over 20 damage per second in place there. Then fill the remaining slots, cannons for preference.
5. Once all ten slots are taken — upgrade, starting with cannons towards level 3, then the rapid towers. Never touch the frost towers.

Why the run always ends, and what that changes

Your score is the number of waves survived, and it is worth knowing what you are playing against. Enemy hit points are multiplied by 1.28 every wave: a normal enemy has 8 on wave 1, 21 on wave 5, 74 on wave 10, 254 on wave 15 and 871 on wave 20. That is exponential growth. Your income, meanwhile, grows linearly: wave 1 holds 6 enemies, each wave adds two, and the total caps out at 40 from wave 18.

The gap widens wave after wave, and the table leaves no room for doubt:

• Wave 5 — 363 hit points to destroy, with at most 331 money earned since the start. Roughly 1.1 hit points per unit of money available.
• Wave 10 — 2,064 hit points, for 946 money accumulated. The ratio has moved to 2.2.
• Wave 15 — 10,501 hit points, for 1,912 accumulated. The ratio reaches 5.5.
• Wave 20 — 42,422 hit points, for 3,218 accumulated, when filling all ten slots with maxed cannons costs 3,100. The ratio passes 13.

No strategy reverses that curve: a board saturated with level-3 cannons tops out at 693 damage per second, nowhere near enough against a wave 20. The run ends, and the only stake is when. That is precisely why the return on your first purchases weighs so heavily: every slice of money misplaced early delays your whole development, and costs you a wave or two at the finish.