The Quick Answer
| Closed Beta Dates | June 5 – June 7, 2026 |
| Developer | ACE Team |
| Platforms | PC (Steam) |
| Launch Discount | 10% off (unlocked via wishlist milestones) |
ACE Team Opens the Jungle Gates Early
With The Mound: Omen of Cthulhu set to release on July 15, 2026, players do not have to wait until next month to experience its tense multiplayer horror. Developer ACE Team is hosting a closed beta playtest starting today, running through the weekend of June 5 to June 7, 2026.
This playtest gives cooperative squads their first hands-on look at how the game handles sanity-draining environments. Known for their unorthodox world-building in games like Clash: Artifacts of Chaos and the Zeno Clash series, ACE Team seems to be bringing that same surreal energy to a 19th-century expedition.
For more details on what platforms will support the final release, check out our release, platform, and pricing breakdown.
How to Register for the Closed Beta
Sign-ups are currently open for the weekend playtest. Since this is a closed beta, player slots may be limited based on server capacity.
- Platform: The playtest is running on PC via Steam.
- How to Sign Up: You can request access directly on the game's Steam store page or through official developer sign-up links distributed via community channels.
- Co-op Focus: The beta focuses on the core online co-op mode, allowing you to team up with friends to test the group dynamics under pressure.
If you are wondering how the co-op systems will function in the final release, read our guide on co-op and crossplay features.
Steam Milestone Unlocks a Launch Discount
Alongside the playtest announcement, Steam news confirmed that the community has successfully unlocked the first wishlist milestone. Everyone who purchases the game at launch will receive a 10% discount.
According to the developers, the entry price into the jungle drops further as more players add the game to their wishlists. This is a welcome incentive for squads looking to jump in together on day one without paying full price.
For a broader look at previous testing phases and wishlist rewards, you can read our wishlist and demo guide.
Reality-Bending Sanity Mechanics
Recent hands-on previews from outlets like IGN have compared the game’s mental degradation effects to the classic Eternal Darkness: Sanity’s Requiem. Rather than just lowering a stat bar, losing sanity in The Mound forces players to second-guess what they see and hear.
In a co-op setting, these auditory and visual hallucinations can lead to player paranoia, where teammates might view completely different realities. We have broken down how these psychological threats affect your survival in our analysis of the sanity system.
While the exact list of sanity effects remains under wrap (and we expect to see more variations during this weekend's playtest), the promise of meta-horror elements makes this one of the more unique co-op horror titles coming this summer.
FAQ
How do I sign up for the closed beta?
You can sign up directly on the Steam page by requesting playtest access.
When is the release date for The Mound: Omen of Cthulhu?
The game is scheduled to launch on PC and other platforms on July 15, 2026.
What is the launch discount for the game?
Due to wishlist milestones being reached, the community has secured a 10% launch discount on Steam.