A 3D tower defense game you can play free in your browser. Build ballistas, cannons, catapults and storm towers along the road, upgrade them, and hold the citadel for ten waves of raiders, armoured brutes, healing shamans and flying invaders. Three battlefields, three difficulties, and three stars to earn on each.
- Genre
- Strategy
- Players
- Single player
- Devices
- Phone and desktop
- Price
- Free, plays in the browser, nothing to install
How to play
Tap a tower card, then tap an open grass tile to build. Tap a tower to upgrade, retarget or sell it. Sky Strike: tap the button, then the board. Keys: 1-4 towers, Space sends the next wave early for bonus gold, Q strike, U upgrade, T target, F speed, P pause.
New in v2.6
The battle menu now fits phones held sideways, small labels are easier to read, and anonymous gameplay stats help us tune the waves.
How to play Citadel Skies
Enemies march along the road from the portal to your citadel. Every one that reaches the gate costs integrity, and when integrity hits zero the battle is lost. Survive all ten waves to secure the battlefield.
- Pick a tower from your arsenal, then tap an open grass tile beside the road. Trees, rocks and the road itself cannot be built on.
- Earn gold for every enemy you defeat and for every wave you clear.
- Upgrade a tower by tapping it. Each tower has three levels, and every level adds damage, fire rate and range.
- Send waves early. Between waves a countdown runs. Sending the next wave before it finishes pays bonus gold for every second you skip.
You start every battle with one free Ballista, and the first wave arrives a few seconds after you press Play.
Towers
- Ballista (70 gold): fast bolts that hit ground and air, with bonus damage against fliers.
- Cannon (105 gold): splash damage that ignores armour. Ground only.
- Catapult (130 gold): huge range and a wide blast, but slow and lobbed, so it leads its targets. Ground only.
- Storm (140 gold): lightning that chains between enemies and slows everything it hits. Ground and air.
Every tower can target the first enemy on the road, the strongest, or the last.
Enemies
- Raiders and Runners are the rank and file. Runners are fast and fragile.
- Brutes wear plate armour that blunts bolts and lightning. Cannons and Catapults cut straight through it.
- Shamans heal everything around them. Kill them first.
- Flyers and Strikers ignore the road and fly straight at the gate. Only Ballistas and Storm towers can hit them.
- The Warlord (wave 5) and the Overlord (wave 10) are bosses. The Overlord flies, and if it reaches the gate it takes ten integrity with it.
Sky Strike
Once every 40 seconds you can call down a meteor anywhere on the battlefield. It deals heavy damage in a wide circle and ignores armour. Save it for a boss, or for a crowd bunched up at a corner.
Strategy tips
- Build where the road bends. A tower at the inside of a corner covers the road twice.
- Have at least two towers that can hit air before wave 3, when the first fliers arrive.
- Upgrading is usually better value than spreading out with level 1 towers.
- Set a Storm tower to target the strongest enemy to slow down bosses and brutes.
Battlefields and stars
Three battlefields unlock in order: Briar Pass, Frostline and Ember Crown. Finish a battlefield with at least 90% of the gate standing for three stars, or at least half for two. Scout is relaxed, Veteran is balanced and Siege is brutal.
FAQ
Is Citadel Skies free? Yes. It runs in your browser with nothing to install, on desktop and on phones.
Can I play tower defense on my phone? Yes. Everything works by tapping: pick a tower card, then tap a tile.
How do I beat the flying enemies? Fliers skip the road, so only Ballistas and Storm towers can hit them. Place them near the citadel, where every flight path ends.
Is my progress saved? Unlocked battlefields and stars are saved to your profile, and your best score goes on the leaderboard.
