Devlog #103: Co-Op Beta - Playtest Launch & Changelog

🚀 First Co-op Beta Playtest Releasing to Players

After months of testing and iteration, we’ve reached a version of the co-op mode that, while not perfect, is stable enough to be shared with players. This marks a huge milestone for the project — and your feedback and bug reports have played a critical role in getting us here. Thank you.

This release is available as a public_testing beta playtest, and we encourage all notified players interested in multiplayer to give it a try. It’s still a work-in-progress, but we believe it’s good enough to start real gameplay and stress testing.

We are already working on a hotfix update that addresses some of the most urgent known issues. We’re also preparing the next version of the update with more content and deeper systemic changes.

This build doesn’t include everything we originally planned — it’s a compromise between overall stability and the need to finally get co-op into your hands.

Over the last two years, 1,510 co-op–related tickets have passed through our tracker — covering bugs, suggestions, and task implementations. What you see in this devlog is only a small slice of what separates the last public version from this current co-op beta.

In parallel, we’ve also worked through a large number of general improvements unrelated to multiplayer — including crash handling, graphics quality, stability, performance and other foundational systems.

Many of those additional tasks are still in progress. Some of the things we’re building now won’t be visible until a month, two, or three from now.

Thank you for your trust, feedback, and ongoing support. Let’s keep pushing this mission forward — together.

The Occupy Mars Team

🔧 How to Join and Host Co-Op Sessions

To access the Co-op Beta, you need to switch your game branch to public_testing on Steam. Important: If you haven’t previously signed up for the beta or participated in pre-EarlyAccess playtests, the co-op mode will not be working for you unless you sign up for the Occupy Mars: Co-Op Playtest button.

How to activate the first co-op playtest:

1. Open Steam and go to your Library.

2. Make sure the product Occupy Mars: Co-Op Playtest is visible in your game library.

3. CosmeticRight-click on the main game/Occupy Mars: The Game and select Properties .

4. In the left-hand menu, click the BETAS tab.

5. In the dropdown labeled “Select the beta you would like to opt into”, choose: public_testing - public testing version

6. Close the Properties window — Steam will automatically download the beta version.

7. Once updated, the game should display [public_testing] next to the title in Steam.

If you don't see the beta tab:

• Make sure you're online in Steam.

• Try restarting the Steam client.

If you launched the public_testing don't have the co-op buttons active in the game's main menu:

• Wait for the next batch of playtest invites as we scale up and let more martians in.

🧭 Starting and Joining Co-op Games

After launching the game, go to Start Game → Multiplayer (or click Online CoOp (Beta)).

To host a game:

• Click Create Game. While most settings are currently locked, you can:

  • Choose the starting location.

  • Select a save to continue from.

  • Copy the join code to share with other players.

To join a game:

• Use Search Game in the Multiplayer menu, or:

• Choose Join Game and paste the lobby code provided by the host.

If you're the host, you'll see a notification with the nickname of any player requesting to join.