Kingdom Tower Defense

The name promises towers. There are none. Nothing to place, no grid, no build phase between waves. What Kingdom Tower Defense gives you instead is one defender, fixed on a castle gate, who swings through a 95-degree arc and shoots for as long as you hold the button.

That sounds like a downgrade until you notice what it does to the decisions. In a maze game your best play is geometry: bend the path, buy time, let the towers do the arithmetic. Here the path is fixed and the geometry is gone, so everything rests on the other half of the equation — how much damage you put out per second, and how long you can keep an enemy in front of you. The five spells on the number keys are the levers.

It is bigger than it looks from the menu. The stage select shows eight tiles, then a second page with eight more: 16 stages, 43 waves, 1,173 enemies. Stage 1 sends 8 of the weakest type and pays 40 gold. Stage 16 opens with a single 2,000 HP boss and follows it with 200 more.

It was published on 28 August 2019 by Kiz10 under its original name, Sentry Guardian, and re-titled for wider distribution in November 2021. Kiz10's own page rates it 2.5 out of 5 from 84 votes, which is worth knowing going in: this is a grind-shaped game, and the grind is the reason for most of those votes.

Where tower defense came from, and why this one is a different branch

The genre has a clean paper trail. Rampart, an Atari Games arcade cabinet from 1990, is generally credited with establishing the template: defences placed by the player, and a loop split into build, defend and repair phases. Then it went quiet for a decade, largely because placing things precisely needs a mouse.

It came back inside other people's games. Custom maps for StarCraft: Brood War — Turret Defense in May 2000, Sunken Defense in November 2001 — were the first widely played examples, and two Warcraft III maps from February 2006, Element TD and Gem Tower Defense, are the ones usually named as the spark. To play any of them you needed the retail game and a map download.

Desktop Tower Defense ended that. Paul Preece put it on the web on 3 March 2007; it recorded 15.7 million plays within four months, took an award at the 2008 Independent Games Festival, and landed on Time's list of the 100 greatest video games in 2012. It also defined the genre's core trick: the enemy route is not drawn in, the towers themselves are the walls, and creeps take the shortest path they can find to the exit. Building a long, winding corridor out of your own towers is called mazing.

Kingdom Tower Defense sits on the other branch, the castle defence line, where the approach is fixed and you are the gun. It simply removes one of the two variables.

The maze you cannot build: why Ice Blast matters more than damage

Here is the arithmetic that makes mazing so strong. The damage an enemy takes on its way in is firepower multiplied by the seconds it spends under fire. Doubling the length of the walk doubles what every tower deals, and it costs nothing but layout; doubling a tower's damage costs gold and improves one tower. That is why, in an open-field tower defense, a good maze usually beats a good upgrade.

This game deletes the layout half of that equation. The route is fixed, so the only way to buy seconds is to slow the clock — which is what Ice Blast does, to every enemy on screen at once rather than in a radius.

The numbers are exact. At level 1 it runs enemies at 0.70 speed for 4 seconds. At level 5, 0.40 speed for 8 seconds — every enemy on screen spends two and a half times longer inside your firing arc, twice as often. No damage upgrade comes close to a 150 per cent multiplier on your entire output. Ice Blast is the maze, sold as a spell.

Thunderbolt is the odd one out: as you level it, the damage figure in the game's own upgrade table falls from 9 to 5 while the number of targets climbs from 2 to 6 and the cooldown drops from 9 seconds to 5. It stops being a hammer and becomes a sweep.

Every upgrade, and what it actually costs

Eight lines, five levels each, hard stop at the top. These are the real values and prices from the game's own upgrade table.

Upgrade	Level 1	Level 5	Cost of level 1	Cost of all five
Attack Speed (seconds between arrows)	0.9	0.3	40	3,290
Damage (per arrow)	6	14	60	5,760
Health	50	250	80	4,680
Ice Blast (duration / speed)	4 s at 0.70	8 s at 0.40	100	5,100
Fireball (waves × projectiles)	1 × 4	2 × 5	400	5,800
Thunderbolt (targets / cooldown)	2 / 9 s	6 / 5 s	600	7,400
Poison (duration / tick)	5 s / 0.3	7 s / 0.5	700	6,300
Split Shoot (extra arrows / duration)	2 / 5 s	4 / 8 s	800	7,800

The Health line is a trap. Your defender starts with 100 HP. The first level of Health sets the maximum to 50. Level 2 gives you 70. Only level 3, at a cumulative 1,180 gold, puts you back to the 100 you began with. Damage and Attack Speed both improve on their defaults from the very first purchase; Health is the only line that starts by taking something away.

Now the total. Maxing all eight lines costs 46,130 gold. A clean run through all 16 stages pays roughly 8,000. That is close to six full campaigns to buy everything, which is the honest shape of the game: it expects you to replay stages for money, and the half-gold-on-defeat rule exists so that farming a stage you cannot yet beat is still worth doing.

Sixteen stages, and what changes along the way

The backdrop tracks how far you have come: stages 1 to 4 run in daylight, 5 to 8 in the afternoon, and everything from 9 onward at night.

The roster grows on a schedule. Type 1 (15 HP) is all you see in stage 1. A ranged attacker joins in stage 2, a 40 HP bruiser in stage 4, the 140-speed sprinter in stage 7, a 30 HP runner in stage 9, a 50 HP ranged unit in stage 12. Then the shape breaks: stages 13, 14 and 15 drop the multi-wave structure and send one continuous wave of 120, 140 and 160. Stage 16 spawns the game's only boss — 2,000 HP, worth 500 gold, forty times the health of anything else on screen — and runs 200 more enemies behind it.

Playing Kingdom Tower Defense unblocked at school

The reason this one gets through school filters is structural rather than lucky. It is a single Construct 2 export — one HTML page, one script, a folder of images — with no plugin, no installer and no account. It saves your gold, upgrades and unlocked stages to the browser's own storage, so a Chromebook handles it the way a desktop does and your progress is still there next lesson, on that machine, in that browser. The flip side: clearing site data wipes the lot and your 16 stages go back to one.

More games in this vein

This is the first strategy sheet on the site, so its closest neighbours are the other games built around a single clean aim-and-shoot decision. Hunter Assassin is the sharpest: one knife, one shadow, and guards whose torch beams do the work a maze does. Warfare Area is a first-person clear-out of 140 enemies through one military base. Stickman Gun Shooter 3D keeps the aiming and drops everything else, and 12 MiniBattles is the one to open when a second person walks in. The rest is in the strategy category.

1. Hold to fire. Hold anywhere on the play area and your defender turns towards the pointer, loosing arrows continuously. On a phone, hold and drag. You cannot aim behind you: the turn is clamped to a 95-degree arc facing the approach.
2. Cast with the number keys. 1 is Fireball, 2 is Ice Blast, 3 is Thunderbolt, 4 is Poison, 5 is Split Shoot. Only Fireball is unlocked at the start; the other four sit behind a padlock until you buy their first level.
3. Survive the wave list. Each stage runs a fixed sequence of waves with a set enemy count and a cap on how many appear at once. Clear the last one and the stage is won.
4. Bank the gold. Every kill drops gold. Win and you keep all of it; lose and you still keep half, so a failed run is not wasted.
5. Spend it in the upgrade screen, then replay earlier stages to fund the next purchase. Only a win unlocks the next stage.

Four things worth knowing before your first stage:

• Buy Attack Speed first. At 40 gold it is the cheapest thing in the shop, and it takes the gap between arrows from 1.0 down to 0.9 seconds. Damage at 60 gold is the next best value.
• Do not buy Health early. The first level sets your maximum to 50, and you start the game with 100. See below.
• Ice Blast is not a damage spell. It is the most important button in the game and it deals nothing at all.
• Watch for enemy type 4. Only 12 HP, but it moves at 140 — nearly twice the speed of the opening enemies — and attacks every half second. Stage 7 throws ten of them at you on their own as an introduction.