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An armored marine and a combat drone hold a shielded platform while a huge tusked alien boss charges across a purple wasteland.

Sector Defense

The aliens took the world. You hold the line, one sector at a time.

Deploy freeAndroid now, iPhone soon

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Free on Google Play from September 30, 202650 sectors13 languages

Sector Defense is a free sci-fi tower defense game for iPhone and Android with a roguelike upgrade draft. You play the marine on the front line: move left and right to shoot forward while combat drones fight beside you, pick new tech as the alien swarm closes in, and take back 50 sectors across four biomes.

What happened to the world?

  1. When they came, everything changed in just a few moments.
  2. I watched our cities fall as the enemy took over our world.
  3. We needed an advantage. So we built combat drones.
  4. We know which places we need to take back.
  5. Now the sector defense begins. And I'm on the front line.

The opening lines of the game, as your marine tells it.

How does a run work?

You don't place towers and wait. You are the defender, on the line, and your arsenal grows mid-fight.

  1. Hold the line

    The swarm comes down the sector toward your wall. Move left and right and your marine shoots forward; the Sentinel drone fires alongside on its own.

  2. Pick your tech

    Kills fill your XP. When it's full, the fight pauses on a Tech Choice: a new drone weapon, an upgrade, or an elite tech that changes how a weapon fires. Spend Dice to reroll the offer.

  3. Take the sector

    Survive every wave and the sector is yours. Your hero, gear and research carry over to the next sector, and the map pushes on.

Tech Choice · XP full

Interactive illustration, not the live game

Pick one. It joins your drone for the rest of the run.

Drone loadout

  • Empty slot
  • Empty slot
  • Empty slot

What do you fight with?

Your marine carries one main weapon. Drone weapons arrive during the run, and every hit lands in one of six elements: Metal, Fire, Electric, Toxic, Void, Plasma.

Main weapons

Assault Rifle
Rapid-fire rifle effective against all enemy types. Your starting weapon.
Pyroblast
Rocket that explodes at the first enemy and can apply Burn. Aimable.
Voidpiercer
Massive void projectile that penetrates enemies. Aimable.
Vulcan
High-speed rotating cannon, a continuous storm of bullets.
Lancerion
Main laser built for extreme penetration and precision.

Drone weapons

  • AutogunRapid fire
  • HellfireExplosive burn
  • VenomSlow and vulnerable
  • RailgunParalyzes enemies
  • Void WavePush and disruption
  • Plasma LancePrecision beam
  • RicochetBouncing shots
  • ChainlightRicochet shock
  • LinebreakerPiercing beam
  • ThunderstrikeArea shock
  • BulletstormRapid spread
  • Gas CloudToxic slow zone
  • Rift OrbPiercing rebound
  • LongshotSingle-target specialist
  • HornetHoming rockets

What are you up against?

The swarm comes in classes. Light creatures come in numbers, heavies soak fire, elites breed and snipe, and the bosses break walls.

Mordax, a boss alien

Mordax

Boss

A colossal armored beast that tears through defenses with its massive tusks.

Vorgath, a boss alien

Vorgath

Boss

A towering brute that crushes defenses with devastating melee attacks.

Light

  • Skitter

    A small, fast creature that attacks in large numbers.

  • Shrike

    A swift flying predator that attacks from the air.

  • Blister

    An unstable creature that explodes upon reaching the base.

Medium

  • Spitter

    Attacks from range by launching toxic projectiles.

  • Reaver

    A resilient predator with balanced speed and durability.

  • Burrower

    Burrows underground, becoming untargetable while moving beneath the surface.

  • Screecher

    Lets out a piercing cry before surging forward at increased speed.

Heavy

  • Crusher

    A massive, durable creature capable of absorbing heavy fire.

  • Leviathan

    A heavily armored flying creature that attacks from the air.

  • Broodworm

    Emerges from underground and continuously releases Skitters until destroyed.

Elite

  • Spinecaster

    An elite ranged predator that launches deadly biological projectiles.

  • Matriarch

    An elite breeder that releases a swarm of Skitters upon death.

Who's on the line with you?

17 heroes, each tied to an element, plus the gear, gems, artifacts and walls that make your defense yours.

Garrick Voss

Metal element

His father died protecting him during the first invasion. Now he believes the broken world can still be rebuilt, one order at a time.

Heroes
A roster of 17 heroes, each tied to an element. Raise their star level with Hero contracts.
Gear and gems
Armor, helmet, belt, pants, gloves and boots. Gems socket into gear and merge into stronger ones.
Artifacts
Relics like the Plague Mask, the Lucky Paw, the Photon Core and the Titan Heart, each a permanent bonus.
Walls
Seven perimeter walls, from the colonial Ironhold to the forbidden Void tech of the Nullgate.

Where do you fight?

50 campaign sectors across four biomes, then Heroic mode sends you through all 50 again, harder.

  1. Desert

    Defend the desert area.

    SECTORS 1–10

  2. Green Forest

    Patrol the wide nature.

    SECTORS 11–20

  3. City

    Protect valuable resources.

    SECTORS 21–30

  4. Arctic

    Defend the citizens of the Arctic zone.

    SECTORS 31–40

Sectors 41 to 50 take the war back to the desert.

Beyond the campaign

Heroic mode
All 50 sectors again, harder, for players who cleared the campaign.
Gas Tunnels
Clear the areas and destroy the nests for rare resources. The insects get stronger as you go, and the Brood Colossus lives down there.
Daily challenges
Fresh challenge stages every day, plus leaderboards for enemies slain and tunnel progress.
Events and passes
Rotating events and a Battle Pass with their own reward tracks.

Your base, even offline

Your base keeps mining while you're away: resources pile up offline, up to the maximum mining time, and wait for you to collect them. Auto-pick tech and auto next sector let the game play on when you'd rather watch.

Energy Core
Energy is processed here. You can't go on a mission without it.
Crystal Mine
Processes the crystals that enhance your equipment.
Gas Processing
Refines raw gas, the upgrade material for your defense.
Gold Mine
Extracts and processes gold.
Laboratory
Runs the Research Tree between missions.
Command Center
Dispatches your hero on special challenge missions.

What does it look like?

A 23-second trailer and the store screenshots, straight from the game's listing.

Questions from the field

If you like tower defense, roguelike survivors, alien-swarm sci-fi or RTS marines holding a choke point, Sector Defense sits where those overlap.

What is Sector Defense?

Sector Defense is a free mobile tower defense game with a roguelike upgrade draft, set in a sci-fi war against an alien swarm. You play the marine on the front line of a sector: move left and right to shoot forward, fight beside combat drones, and pick new tech between enemy pushes. It is made by NOXGAMES for Android and iOS.

When does Sector Defense come out?

Sector Defense launches on Google Play on September 30, 2026. It is built for iPhone and iPad as well.

Is Sector Defense free to play?

Yes. The campaign is free to play. The game has optional in-app purchases and ads.

Which phones does it run on?

Android phones and tablets running Android 7.1 or later, and iPhone and iPad running iOS 15 or later. It plays in portrait.

How is it different from other tower defense games?

You don't place towers and watch. You are the defender: your marine moves along the line and shoots forward, drones fire alongside, and the weapons you fight with arrive mid-run as Tech Choices. Every run builds a different loadout, and element matchups matter more than placement.

What are the aliens?

The swarm ranges from Skitters that attack in large numbers and flying Shrikes to Burrowers that go untargetable underground, Broodworms that keep spawning Skitters, and elite Matriarchs and Spinecasters. The bosses are Mordax, a colossal tusked beast, and Vorgath, a towering brute.

How many levels are there?

The campaign has 50 sectors across four biomes: desert, green forest, a ruined city and the arctic. Heroic mode replays all 50 at a higher difficulty, and the Gas Tunnels and daily challenges add more.

Which weapons can I use?

Your marine carries a main weapon: Assault Rifle, Pyroblast, Voidpiercer, Vulcan or Lancerion. Drone weapons arrive during the run, including Autogun, Hellfire, Venom, Railgun, Void Wave, Plasma Lance, Chainlight, Linebreaker, Thunderstrike, Bulletstorm, Gas Cloud, Rift Orb, Longshot and Hornet.

Does Sector Defense work offline?

Your base keeps mining resources while the game is closed, up to the maximum mining time, and they're waiting when you come back.

Is there PvP?

No. Sector Defense is a single-player game, with leaderboards for things like enemies slain and Gas Tunnels progress.

What languages is it in?

13 languages: English, Czech, German, Spanish, French, Japanese, Korean, Polish, Portuguese (Brazil), Russian, Turkish, Ukrainian, Vietnamese.

Who makes Sector Defense?

Sector Defense is developed and published by NOXGAMES s.r.o., an independent mobile game studio based in Prague, Czech Republic.

How do I contact support or report a bug?

Use the support form on the Support page or email support@noxgames.com. Include your player ID if you have it, so the team can find your account faster.

Fifty sectors. You start at one.

  1. Desert

    01–10

  2. Green Forest

    11–20

  3. City

    21–30

  4. Arctic

    31–40

  5. Desert

    41–50

The campaign map: four biomes, then the desert again for sectors 41 to 50. Heroic mode runs all fifty a second time.

Free on Google Play from September 30, 2026. The iPhone version is on its way.

Deploy freeAndroid now, iPhone soon

Writing about the game? The press kit has the fact sheet, logo and art.