Space Defense Engineer
A dropship descends towards a colony on an orange planet, with a rocket pad, a monorail and a ringed gas giant filling the sky.

Orbital contract network // Free download

Space Defense Engineer

Take the contract. Ride the dropship down. Build a colony's defences along the canyon, command the crews who keep them firing, and hold it against everything the raiders send.

Download free

For Windows, macOS and Android. Version 2.1.0.

The game

Your base is the battlefield.

A tower defence where every turret you place and every upgrade you buy visibly grows the colony around you.

The tactical view: towers on terraced ground around a winding canyon road, under attack.

Build along the canyon

Raiders follow the road to your HQ, shooting whatever they pass, while aircraft fly straight at it and send drones ahead. Place guns on the rims, take the high ground for extra range, and keep your power grid in the black, because an overloaded grid slows every gun you own.

A squad of gunners selected at the edge of the canyon as a shuttle comes in to collect them.

Command your crews

Circle your units and right-click to send them. Engineers repair what's been hit, gunners crew your turrets, and fighters fly where you need them. Nobody crosses the canyon on foot: units wait at the edge for a shuttle to fly them over.

A close view of the colony's white modules, joined by tunnels, with a dome and a landing pad.

Upgrades you can see

Each tier stacks a tower higher on stilts and modules. Drill crystal deposits for income, raise habitats that link up with tunnels, and watch a landing site turn into a town.

The HQ terminal in light grey and orange, with contracts on the left and your base floating in the centre.

Pick your next job

Every contract has its own planet, route, hazard and payout, and you can survey it before you sign. Bank your pay to grow your HQ, license new weapons and take on harder work.

Five worlds

No two contracts look alike.

Each planet has its own colours, sky, light and weather, on a battlefield generated fresh for every contract.

Rust Basin
Rust BasinIron desert under a copper dusk
Pale Regolith
Pale RegolithAirless moon, black sky
Glacier Shelf
Glacier ShelfBlue ice and falling snow
Verdigris Flats
Verdigris FlatsGreen crust, sulphur haze
Cinder Reach
Cinder ReachBlack glass and a violet night

Arsenal

Eleven structures. Twelve ways to lose a colony.

Six turrets, five support buildings and four kinds of unit to answer swarms, armour, shields, aircraft and bosses, plus an orbital strike, an EMP and a repair burst for when it all goes wrong.

Turrets

Pulse CannonAll-rounder

Reliable bolts against anything that moves or flies.

Twin RepeaterRapid fire

Shreds swarms and light craft. Armour blunts it.

Siege MortarSplash

Slow arcing shells that wreck ground formations.

Arc CoilChain, slow

Lightning that jumps between targets and bogs them down.

Missile BatteryAnti-air

Guided warheads with double damage against aircraft.

Rail LancePierce

A hypersonic slug through everything on the line.

Your forces

EngineerRepair, boost

Fixes what's in reach. Upgraded, it overclocks everything around it.

GunnerCrew

A rifle in the open, or crew inside a turret that then shoots harder.

ShuttleAirlift

Comes for units waiting at the canyon, or flies them anywhere.

FighterAir and ground

A strike craft you send around the map to hunt what gets through.

The raiders

SkitterSwarm

Fast, fragile, and never alone.

TrooperInfantry

Foot soldiers who stop to shoot whatever's in reach.

BulwarkShielded

A regenerating shield. Don't let up.

GunshipAircraft

Ignores the road, launches drone strikes and knocks structures offline.

Warlord RigMini-boss

Every fourth wave brings something like this.

Colossus ConvoyBoss

The last thing you see on a bad day.

Version 2.1.0

Download

Free, with no account and no ads. Your progress saves on your device.

Windows

Windows 10 or later, 64-bit, with a Vulkan graphics card.

Zip, 76 MB Download for Windows SHA-256 2e06db9d79652a77c2fb9c934eea1e5639a862dbdee0ebbb42d45cd3b97b2983

macOS

macOS 11 or later on Apple silicon, or 10.15 or later on Intel.

Zip, 98 MB Download for macOS SHA-256 dd44a3053b82205c5eff2f75b95584bc6857caf4d805994dc51261c3576e49f6

Android

Android 7 or later on a 64-bit phone with Vulkan. Plays by touch.

APK, 66 MB Download for Android SHA-256 d3311f259c621631ca125ccaa473e2c67f44951400d793a5a81c3b0317cc2049

Install

  • Windows: extract the whole zip and run Space Defense Engineer.exe, keeping the .pck file beside it. The build isn't code-signed, so if SmartScreen warns you, choose More info, then Run anyway.
  • macOS: extract the zip and open the app. It isn't notarized, so macOS refuses it the first time: choose Done, then System Settings > Privacy & Security > Open Anyway.
  • Android: download the APK on your phone and open it. Android asks you to allow installs from your browser the first time.

Controls

WASD, wheelPan and zoom
Q EOrbit the camera
1-0, clickPick and place a structure
U X TUpgrade, sell, targeting
Z C V BTrain an engineer, gunner, shuttle, fighter
Left dragCircle units to select them
Right clickMove, crew a turret, attack a hostile
LAirlift the selected units
F G ROrbital strike, EMP, repair burst
Space, TabLaunch wave, game speed
TouchDrag to pan, pinch to zoom, tap a card and drag it onto the ground. Tap a unit, or LASSO and draw, then tap where to send it