Co-op Tower Defense with Friends

Can you play tower defense online with friends?

Yes. Start a match, copy the invite link and send it to your friends – they land right on the same map. Up to 4 players defend the Atlas together.

Can you join or leave a match that's already running?

Yes. With the invite link, friends can join at any time – even at wave one hundred – and play right away as long as a slot is free (up to 4 players). Anyone who leaves keeps their towers standing; their gold goes to the teammates, and reloading brings them back.

What happens when a teammate goes AFK?

Nothing bad – nobody gets kicked and the team stays in action. Anyone idle for a while counts as away: their gold is automatically shared among the active teammates, and new income only goes to them. As soon as they do something again, they're back in the game.

What does the game cost – do I need to install anything?

Nothing. Atlas Defense runs for free in your browser – no download, no account, no sign-up.

How is gold shared in co-op?

Everyone has their own wallet, but all income is split evenly among the active players. Nobody can grab the team's gold; you fund Atlas upgrades together in partial payments.

Can I play alone too?

Yes. Waves are the same solo and in a team – as a team you just share gold and tasks. Teammates can join at any time.

Can viewers just join while I'm streaming?

No. The room code in the address bar is not enough – only people with the private invite link can join. The link is never shown, only copied to your clipboard.

Atlas Defense: co-op and controls

Create a room and share its eight-character code. Up to four players build on one authoritative map with separate wallets. The room creator can remove teammates. Chat opens with Enter or a click. On desktop it stays transparent and can be dragged. Teammates have small colored cursors; team markers last eight seconds.

Double-click an owned tower to select all owned towers of that type and level. Upgrade, specialize, change priorities or sell the selection together. Specialization shows total gold and the amount missing. On touch devices, choose a building and position, then confirm. The lower Build, Orders and More tabs can be collapsed.

Atlas, pylons and bridges

Pylon range comes first in the Atlas menu; Protocol Zero is last. Each pylon range level adds 3% of its original six-tile range, up to ten levels. Existing pylons and connections update immediately. The Atlas power radius remains eight tiles. The pylon limit starts at six and increases by three every 25 waves. Each pylon costs 100 gold.

A defence bridge costs 10,000 gold with shared funding. Choose a valid position on the crystal scar and north or south as the defence side. Ground enemies cross to that side; flying enemies are unaffected. A faint planning preview appears before building. Demolition gives no refund and waits for enemies to leave safely.

Difficulty, waves and gold help

Choose before starting: Relaxed (80% enemy HP), Standard (100%), Hard (125% and 15% extra combat/wave gold), or Ultra (150%, no extra gold). Relaxed and Standard use original Atlas prices; Hard and Ultra keep increased prices. Difficulty is locked during play and leaderboards have separate filters.

Every 25th wave adds another 15% HP. Clearing a milestone awards 250 gold per active player and repairs up to 10% of maximum Atlas health, rounded up. The reward is paid once. Hard's bonus does not multiply starting gold, transfers, refunds, casino wins or fixed milestone rewards.

Each connected player approves 0–25 early waves. The lowest approval applies; up to 25 waves may be active. Gold help transfers 50, 100, 250 or 500 gold to an active teammate without fees. Restart and quit need approval from all connected teammates.

Planning, daily maps and the crystal slot machine

The optional daily map uses the current date in Europe/Berlin as DDMMYYYY (13 October 2026: 13102026). Random maps and manual seeds remain available. Running maps never change at midnight. The wave preview highlights flying enemies, armor and swarms. The tower overview shows counts, levels, specializations, damage, kills and investment.

The crystal slot machine can run in a compact background window while you build. Automatic paid spins must be explicitly enabled and can be stopped. Free spins continue in the background. FPS appears at the upper left.

Rooms and chat stay in server memory and end on server restart. Game saves are disabled. Server leaderboards persist separately.

Compact controls

Click the Atlas in the center to open its upgrades. Wave approval is in the top bar; Space starts or calls waves early with the existing team approval. The lower action bar contains Bridge, Mark, Tower overview and Crystals & radio. Gold help and Leave room are in the co-op settings.

Crystal weapons, shards and radio

Build an owned tower on crystal ground, upgrade it to level 3 and choose a specialization (J/K). Then select Crystal upgrade in the tower menu or press L. Pay with shards. Each additional owned crystal weapon increases the price by 10% of the base cost.

Kills on crystal ground or in a Resonator field add shards worth 10% of the kill reward. Crystal weapon kills add another 10%. Fractions accumulate; active teammates share whole units.

Radio: kills contribute 0.25 and combos 0.1, limited by a shared budget. The budget refills at 36 radio per simulation minute and stores 60; waiting alone does not credit radio. Bosses grant 80 extra radio. The base player limit is 600. The Atlas radio upgrade increases capacity and budget. Radio pays for support orders, which also have cooldowns.

Solo: north only or both sides

Choose your solo defence sides before starting. North only routes future spawns through northern entries. Enemy count, HP and rewards stay the same. With two connected players both sides are enabled. If only one remains connected, the chosen solo rule applies to enemies that have not spawned yet. Living enemies are never moved.

Text chat, emojis and voice chat

In co-op, press Enter or click the room chat. Use ☺ to insert an emoji at the cursor and send it with your message. On desktop, chat stays visible with a transparent background and can be dragged by its title; on mobile, you can collapse it.

Each participant clicks “Join voice” and grants microphone permission to speak. “Mute” switches off your microphone; the volume slider controls the other voices. The participant list shows who joined, is muted or connected. If your browser blocks playback, click “Enable audio playback”.

Voice is optional and limited to participants in the same room. The microphone stops when you leave voice, leave the room or lose the game-server connection. After reconnecting, join voice again. There is no recording. Use the HTTPS game address and preferably headphones. If voices do not connect despite microphone permission, the operator may need to configure a TURN server.