Alien Siege: tower defense game online free
Alien Siege is a free tower defense game in the style of Alien Creeps TD that you can play online in any browser. Waves of aliens pour out of purple portals and march down winding roads toward your command base. Build and upgrade towers, move your hero commando to block them, call in a helicopter gunship and airstrikes, and beat 40 levels in four worlds with bosses, stars and research upgrades.
How to play Alien Siege
- Choose a mission: the 40-level Campaign, Endless or the Daily siege.
- Tap a pad beside the road and choose a tower to build it.
- Tap the orange flag at the alien portal, or press Space, to call the first wave.
- Destroy aliens to earn energy, then tap your towers to upgrade them.
- Move your hero to block the road, and call in the helicopter and airstrikes.
- Survive every wave before the aliens use up your 20 lives to win the level.
On a computer you can also press Space to call the next wave, F for fast forward, H to select your hero, C for the helicopter, B for the airstrike and P or Escape to pause. Calling a wave before its countdown ends gives you bonus energy.
Towers and upgrades
| Tower | Cost | What it does | Flyers |
|---|---|---|---|
| 🔫 Blaster | 70 | A fast machine gun; elite level: twin miniguns | Yes |
| 🚀 Rocket Pod | 110 | Homing rockets with splash damage; elite level: double rockets | Yes |
| ❄️ Cryo | 85 | Freezing pulses slow and hurt every alien around it | Yes |
| 🔆 Laser | 130 | A beam that heats up on one target and ignores armour; elite level: chain beam | No |
Tap a tower to see its range, upgrade it or sell it for 70% of what you spent. Every tower has three levels you can buy with energy, and a fourth elite level that unlocks with research. The Rocket Pod arrives on level 2, the Cryo tower on level 4 and the Laser on level 7.
The aliens
| Alien | From level | What to know |
|---|---|---|
| 🐛 Grub | 1 | The basic crawler |
| 🕷️ Skitter | 2 | Fast and fragile: slow it with Cryo |
| 🛸 Drone | 4 | Flies over everything; Lasers cannot hit it |
| 🪲 Brute | 5 | Armoured: small bullets barely scratch it, Lasers melt it |
| 🛡️ Shield Bug | 9 | Its energy shield comes back if you stop shooting |
| 🟠 Splitter | 12 | Bursts into three small aliens |
| ➕ Medic | 16 | Heals the aliens around it: kill it first |
| 👑 Hive Queen and 🛸 Mothership | 10, 20, 30, 40 | Huge bosses that lay grubs or launch drones; a boss that gets through costs 10 lives |
Hero, helicopter and airstrike
From level 3 your hero commando joins the fight. Tap him and then the map to move him: he blocks the first alien that reaches him, shoots everything nearby and levels up during the battle. The helicopter gunship (level 5) flies to the spot you tap and strafes every alien around it, and the airstrike (level 8) drops a row of bombs along the road. Both recharge after use, so keep them for big waves and bosses.
The four worlds
| World | Levels | What is new |
|---|---|---|
| 🌴 Jungle Outpost | 1–10 | All four towers, the hero, the helicopter; the Hive Queen |
| 🏜️ Desert Canyon | 11–20 | Splitters, two portals at once; the Mothership |
| ❄️ Frozen Base | 21–30 | Medics, longer sieges with tougher aliens |
| 🌋 Volcano Core | 31–40 | The final front: the Queen and the Mothership together |
Every level has its own map, with roads that wind between rows of tower pads, and later levels open a second alien portal.
Stars and research
Win a level to earn stars: one for a win, two if you keep at least half of your lives and three if you lose at most two. Spend stars in the 🔬 Research lab on eight upgrade tracks: each tower (more damage, more range, the elite level), the hero (health, damage, grenades), the helicopter, the airstrike and the command base (more starting energy, extra lives, more energy per kill). You can reset research at any time to try another plan.
Endless, Daily and leaderboards
Endless is a survival siege on a fresh map: the waves never stop and get tougher every time, with a boss every ten waves. The Daily siege gives everyone the same map and the same 18 waves each day. Both have free leaderboards for today, this week and all time; you only choose a nickname if you want to join.
Badges
There are 25 badges for winning levels and worlds, collecting stars, destroying aliens and bosses, shooting down flyers, hero kills, helicopter missions, big airstrikes, building towers, elite towers, research, flawless wins, Endless waves and daily sieges. Open the medal button in the game to see your progress.
| Badge | How to earn it |
|---|---|
| 🛡️ First Defence | Win your first level. |
| 🌴 Jungle Guard | Complete the Jungle Outpost (level 10). |
| 🏜️ Canyon Keeper | Complete the Desert Canyon (level 20). |
| ❄️ Ice Warden | Complete the Frozen Base (level 30). |
| 🌋 Planet Saviour | Complete the Volcano Core (level 40). |
| ⭐ Decorated | Earn 30 stars. |
| 🌟 War Hero | Earn 75 stars. |
| 🎖️ Supreme Commander | Earn all 120 stars. |
| 👾 Alien Hunter | Destroy 500 aliens. |
| ☄️ Exterminator | Destroy 5,000 aliens. |
| 👑 Queen Slayer | Defeat a boss. |
| 🛸 Sky Shield | Shoot down 200 flying aliens. |
| 🪖 One-Man Army | Your hero defeats 250 aliens. |
| 🚁 Air Cavalry | Call the helicopter 25 times. |
| ✈️ Carpet Bomber | Destroy 8 aliens with one airstrike. |
| 🏗️ Engineer | Build 100 towers. |
| 💠 Elite Arsenal | Build an elite (level 4) tower of every kind. |
| 🔬 Mad Scientist | Buy 12 research upgrades. |
| 💯 Flawless | Win a level without losing a life. |
| 😅 Last Stand | Win a level with a single life left. |
| ⏩ Bring It On | Call 50 waves early. |
| ♾️ Holdout | Reach wave 20 in Endless. |
| 🏆 Unbreakable | Reach wave 40 in Endless. |
| 📅 Daily Duty | Play the Daily siege. |
| 🗓️ Week on the Wall | Play the Daily siege on 7 days. |
Alien Siege tips
- Cover the bends. Pads inside a bend of the road reach two or three stretches of it at once.
- Mix your towers. Blasters and Rocket Pods for flyers, Lasers for armour, Cryo to slow everything down for the others.
- Upgrade before you spread. A level 3 tower is far stronger than two new ones.
- Use your hero as a wall. Park him just after your strongest towers, so blocked aliens stand in their fire.
- Kill medics first and keep shooting shield bugs so their shields cannot come back.
- Call waves early when your defence is strong: the bonus energy adds up fast.
Frequently asked questions
Is Alien Siege free?
Yes. Alien Siege is completely free to play online, with no sign-up, no download and no in-app purchases. It runs in your browser on computers, tablets and phones, and your levels, stars, research and badges are saved on your device.
Is Alien Siege like Alien Creeps TD?
Yes, Alien Siege is an Alien Creeps-style tower defense game: waves of aliens march along a road toward your base, and you stop them with upgradable towers, a hero and air support such as a helicopter and airstrikes. It has its own art, music, maps and features, such as research upgrades and a Daily siege. Alien Creeps is a trademark of Outplay Entertainment; Alien Siege is an independent game and is not affiliated with or endorsed by it.
How do I play Alien Siege?
Aliens come out of a purple portal and follow the road to your command base. Tap a pad beside the road and choose a tower to build it. Towers shoot every alien in range, and each kill gives you energy to build and upgrade more. Survive every wave to win the level; each alien that reaches the base costs a life.
Which towers are there?
The Blaster is a fast machine gun that also hits flyers. The Rocket Pod fires homing rockets with splash damage. The Cryo tower sends out freezing pulses that slow every alien around it. The Laser burns one alien with a beam that grows hotter the longer it stays on target, and it ignores armour, but it cannot hit flyers. Every tower has three levels, and a fourth elite level that you unlock with research.
What does the hero do?
Your hero is a commando. Tap him and then tap the map to move him. He stops the first alien that walks into him and fights it, shoots everything nearby and gets stronger as he gains experience during the level. If he falls, he is back at the base after 12 seconds.
How do the helicopter and the airstrike work?
Tap the helicopter button and then a spot on the map: a gunship flies in and fires at every alien around that spot for several seconds. The airstrike drops a row of bombs along the road where you tap. Both recharge over time, so save them for big waves and bosses.
What is research?
Every level gives up to three stars: you get three when you lose at most two lives. Stars buy research: stronger and longer-range towers, the elite tower levels, a tougher hero with grenades, a longer and deadlier helicopter, bigger airstrikes and a better command base. You can reset research at any time and spend the stars again.
How many levels are there?
The campaign has 40 levels in four worlds: the Jungle Outpost, the Desert Canyon, the Frozen Base and the Volcano Core, with a boss at the end of each world. New towers, aliens and powers unlock as you go. After that, Endless and the Daily siege keep the battle going.
What are the Endless and Daily modes?
Endless gives you a fresh map and waves that never stop and get tougher every time; see how many waves you can hold. The Daily siege is the same map and the same 18 waves for every player that day. Both have free leaderboards for today, this week and all time.
Can I play on a phone?
Yes. Alien Siege works on phones and tablets in portrait and landscape. Tap pads, towers and your hero, and use the round buttons at the bottom for your hero and powers. In portrait the battlefield is turned, so every level plays exactly the same as on a computer.
More strategy and arcade games: Tank Battle, Sea Battle, Marble Serpent and Block Stack.