Circle Defense is free on Steam

CIRCLE is a tower defense game with a light card system, where you will play as a commander defending the Earth: by building/upgrading weapons on a rotating device called "CIRCLE" and using cards to deal with the continuously invading aliens.

Frequently Asked Questions:

How to get it free?

Step 1: Click "Get It Free" button.

Step 2: After clicking the "Get It Free" button, you will be redirected to the game's page on the Steam store. You should see a green "Play Game" or "Add to Library" button on the page. Click it.

Step 3: A new window will open confirming that you want to add the game to your Steam library. Go through the installation prompts by clicking "Next" until you reach the end. Then, click "Finish" to add the game to your library.

Step 4: The game should now be in your Steam library. To play it, you'll need to install it first. Do this by navigating to your library, clicking on the game, and then clicking the "Install" button. Once the game is installed, you can launch it directly from your Steam library.

How can I download Circle Defense?

You should log in to Steam to download and play it for free.

How can I get notified about the free games in the Steam category with the Free Games Discord Bot?

Use the `/cat` command to activate the Steam category. Once activated, when games like Circle Defense become free, the Free Games Discord bot will share them in your Discord server. For more information about the Discord bot, click here.

Which platforms is the game playable?

Circle Defense can playable the following platforms: Windows

What is the genre of the game?

The genres of the game are Single-player .

What languages are available for Circle Defense?

Circle Defense supports the following languages: English*, Simplified Chinese**languages with full audio support

When was Circle Defense released?

The game relased on Q3 2025

Who is the publisher of the game?

RUIAN0577

Who is the developer of the game?

RUIAN0577

Is "Circle Defense" still free?

The game is currently free. If you add the game to your library within the time specified in the free game offer, the game will be permanently yours.

The game has I know you have rich experience in defending the Earth!
CIRCLE is a tower defense game with a light card system, where you will play as a commander defending the Earth: by building/upgrading weapons on a rotating device called "CIRCLE" and using cards to deal with the continuously invading aliens.

Origin of the CIRCLE
One day, the moon was hit and destroyed by unknown creatures, and the debris turned into a circle around the Earth. Due to concerns about the unknown creatures, humans transformed the lunar circle into the CIRCLE device and deployed cosmic-level defense weapons on it.

Technology Cards
Under the pressure of alien attacks, the human military technology tree continues to evolve, and its functions are summarized into command cards, waiting for the commander to issue orders.
The energy for the cards comes from the CIRCLE: the faster the Ring rotates, the higher the energy generation rate, but it seems to affect the aiming rhythm for deploying weapons.

Features
- Level-based game: each successful defense against alien attacks will greatly enhance Earth's weapon defense technology, continuously unlocking new weapon types, upgrade items, and new technology cards.
- The combination of different weapon upgrade projects and different cards will create a multitude of possibilities.
- Each type of monster has its own behavior patterns and characteristics, so make sure to respond based on your understanding of them!
- Besides monsters, you also have to face the harsh cosmic environment, and some levels will force you to abandon common strategies to try more suitable solutions.
- You can press the space bar at any time to slow down time for more time to think about strategies and operations; or maybe you just want to see the fireworks in slow motion?