There is no official campaign length, and there is no honest single number for a game built as a repeatable co-op loop — so here is the structure instead. The loop is the expedition: take a contract aboard the Tempestad, sail in, haul treasure, get out. Demo expeditions run roughly twenty minutes to three-quarters of an hour depending on tier, greed and how loudly things go wrong — a Basic haul is a coffee-length run, a deep push with a full crew is not. Those per-expedition ranges held from the demo into the 1.0 build; we keep timing real distributions as the launch population settles.
The Story line
Story contracts thread the expeditions together: they uncover forts that expand the map, and eventually open the descent that ends at the Mound itself — capped by The Moundachievement. Between Story beats you'll run ordinary contracts for coin, gear and rank, so "beating the story" is a many-evenings arc rather than a weekend sprint.
What 100% asks
The 25 achievements sketch the completionist budget honestly: reach rank 30, unlock the full playable roster (Seven Willing Souls), collect all nine sacred figures, gather all 13 logbooks and the creature codex, revive 50 teammates, and revive fifty teammates. The revive and collection counters alone tell you this is designed as a long-haul co-op habit, not a checklist weekend.
Length questions
How long is The Mound: Omen of Cthulhu?
It's run-based: expeditions last roughly 20–45 minutes in the demo depending on contract tier, and the Story line threads many expeditions together to reach the Mound. There's no fixed campaign length — we'll publish measured run distributions at launch.
How long is the demo?
The demo covers the opening slice — the prologue and early contracts. Most players see what it's selling in one to two hours, and it's free, so the real answer is: until you're convinced.
How long does 100% take?
There's no single honest number yet, but the achievement list implies a long haul: rank 30, the full character roster, all 9 saint figures, all 13 logbooks, 50 teammate revives and a 50%-over treasure quota. It's built as an ongoing co-op game, not a weekend platinum.