// GAME GUIDE //

Clash of Stars

Free online space RTS · 2 to 4 players or solo vs bots · no download, no account

Clash of Stars is a free online space strategy game you play in your browser: every planet you hold builds ships, and you win by sending them to the right places before your rivals do. If you know Galcon, you know the idea; this one runs live online for up to four players, or solo against bots, with no download and no account.

What is Clash of Stars?

Clash of Stars is a real-time strategy game about planets. Every planet you own builds ships by itself, with no orders and no build menu. The only decision you make is which planet sends how many ships where, and you take a planet by landing more ships on it than it has defending.

Combat is counted one ship at a time. A ship arriving at a planet you own adds one to its garrison; a ship arriving anywhere else subtracts one, and the instant it goes below zero the planet changes owner and keeps whatever is left over. There are no unit types, no upgrades and no dice.

A match is played on a field of 14, 20 or 28 planets depending on the map size. You start with a home planet holding 130 ships; every other planet is neutral, holding 2 to 49 defenders scaled to its size. A player is out once they own no planets, and the last one standing wins. On a medium map that takes two to three minutes.

How to play

• Send: drag from one of your planets onto any other planet. The ships leave the moment you give the order.
• Choose a share: a send commits 25, 50, 75 or 100 percent of the garrison. 50 is the default.
• Take neutrals early: a planet nobody owns produces nothing, so every second it sits unclaimed is growth nobody is getting.
• Win: eliminate everyone else. A player who has lost their last planet stays in for 15 more seconds while a fleet is still flying.

Controls

With a mouse: click one of your planets to select it, click again to drop it, double-click to select every planet you own. Drag from a planet and release over another to send; release over empty space and nothing is sent. A plain click on an enemy or neutral planet never sends, so no fleet leaves by accident. Keys 1 to 4 set the send share, A selects all your planets, S every fleet in flight, and Escape pauses.

On touch: the same gestures with a finger, and tap targets get a finger-sized hit area so small planets stay easy to hit on a phone. Tap a swarm in flight to select the whole send, then drag it onto another planet to re-aim it.

Tips from the developers

• Size is production. Output scales with a planet's radius: the largest planet builds more than seven times as fast as the smallest, about one ship every four seconds at the low end against close to two per second at the top. One good capture beats three cheap ones.
• Sending is spending. The ships leave your garrison the instant you order the send, not when they land. A planet you just emptied is the cheapest target on the map, which is why 50 percent is the default and 100 is a gamble.
• Count the travel time. Ships fly at 90 units per second across a 1000 by 1000 field, so a fleet crosses the map in about eleven seconds and takes roughly sixteen corner to corner.
• Pick the bot that matches you. Easy reconsiders only every 5.5 seconds, idles through 60 percent of those turns and aims close to random. Medium thinks every 1.75 seconds, hard every 0.9 seconds, and hard never idles.
• Zap mode runs on a clock. One charged planet sits at the center. Whoever holds it converts a random planet to their color every time it fires, and its charge time ramps from 10 seconds at the start down to 1 second about four minutes in.

Under the hood

Clash of Stars runs a deterministic simulation at 20 ticks per second. In an online match every browser runs that same simulation and the players exchange orders rather than ship positions, so a send is a handful of bytes and the hundreds of ships it becomes are computed on each machine. That is why a four-player game stays responsive on a poor connection. Each client hashes its game state every 40 ticks, so a divergence is caught rather than quietly played out.

The same determinism keeps a match alive when a connection dies. The bot AI runs inside the simulation and needs no network traffic, so a dropped player's slot is handed to it on every machine at the same tick. If they return, they pull a state snapshot from a peer and take their seat back. The full picture of how two browsers stay in step is in How Clash of Stars keeps hundreds of ships in sync.

FAQ

Is Clash of Stars free? Yes. It runs in your browser on BlitzBrawl, there is nothing to download or install, and there is no payment of any kind.

How many players can join a match? Four. A lobby has four seats, and any seat not filled by a person can be filled with a bot, so a match can be two, three or four players in any mix. Use quick match to be paired with whoever else is searching, or open a private lobby and share its four-character code.

Can I play solo? Yes. Single player puts you against one, two or three bots at easy, medium or hard, on a small, medium or large map, in classic or zap mode. The match is simulated in your own browser, so no opponent has to be online.

Do I need an account? No. You can play as a guest, and an anonymous device account keeps your settings and record on that device. To carry the same identity between your phone and your laptop, add an email address and confirm it with a 6-digit code. There is no password.

Does it run on mobile? Yes. Touch is the primary control scheme rather than a port of the mouse controls, and tap targets get a finger-sized hit area so small planets stay reachable on a phone.