The Mound: Omen of Cthulhu Beginner Guide - Co-op, Madness and First Steps

The Mound: Omen of Cthulhu is a four-player co-op horror expedition from ACE Team, published by Nacon and released on Steam on Jul 15, 2026 at $23.99 in the US. It is a first-person game about descending into a cursed jungle, and the store listing is the only official description of what a run contains.

What the store listing says the game is

The store text opens with the pitch: form a group of explorers searching for treasure in a cursed jungle where monstrous creatures alter reality. It is tagged Action and Adventure, and the developer line names ACE Team with Nacon as publisher.

The listing is organised around four ideas, and it names them in capitals on the store page: a co-op expedition for up to four players, a madness system with altered perception, an expedition into the unknown launched from a galleon, and the search for The Mound itself.

How a four-player expedition is set up

The player count is the most repeated number on the listing. Co-op for up to four players appears in the title of the first store section, and the feature tags confirm how a group connects.

Store tag	What it covers
Multi-player	More than one player in the same session
Co-op	Players working through the expedition as a group
Online Co-op	A party formed over the internet
Full controller support	Gamepad input for every listed action
Steam Cloud	Saves carried between machines

That mix points at online parties rather than split screen: there is no Shared/Split Screen tag on this listing, so couch co-op is not one of the advertised arrangements.

The madness system and altered perception

Madness is the system the store text spends the most words on. It says the cursed jungle plays with your perception, that unpredictable threats distort your senses, and that paranoia spreads inside the group until you can no longer trust what you see and what you hear.

What the listing does not publish is how madness is tracked, whether it is a meter, and what it changes mechanically. Nothing on the store page gives a number, a duration or a recovery rule, so this page leaves those blank rather than guessing.

The galleon, contracts and forts

Between expeditions the party is back aboard a galleon. The listing describes signing a contract with the captain to receive gear in exchange for the treasures you bring back, splitting weapons and equipment among the party, and choosing which area of the jungle to explore next.

Once on the mainland the listing says you are on your own, relying on spatialised voice chat to coordinate. Abandoned forts can be discovered during an expedition and their logbooks recovered, which unlocks them as new starting points for later runs. That is the whole progression loop the store page describes.

Price, editions and what is not published

At capture the standard edition was $23.99 against a $29.99 list price, and a Deluxe Edition was listed at $39.99, $31.99 at capture. Four DLC appids are attached to the listing, but the store page does not give them readable names in the data we captured.

The listing covers a Windows build only, with 11 languages listed and English flagged for full audio. There is no published release plan for consoles, no playtime estimate and no item or enemy list. Where the store page is silent, this page stays silent.

Where to go next

The systems behind a run are broken down on How It Plays, the build and the published specs are on Availability, and the launch facts are on Launch & Demo.