Mortal Shell 2 Update: Rotten Autumn Adds 15 Dungeons

What the Rotten Autumn update adds

The Steam post doesn't come with full patch notes. It's a list of highlights plus "additional polishes and bug fixes," so this is everything the studio has named:

None of this costs money. The game itself is still $49.99 on Steam, where it holds a Mostly Positive rating from 79% of 22,206 reviews as of October 22.

Screenshot: Mortal Shell II Rotten Autumn update trailer (Playstack YouTube channel)

The one-minute update trailer runs through the list. At 0:10 a Shell in gold armor with a crowned helmet walks a street buried in red leaves, one of the new shades. At 0:16 the "New music by Sakis Tolis" card plays over a lute player among pumpkins. At 0:26 a white sheep trots across a stone hall, and two seconds later the dungeon title card appears. The end card at 1:02 says "Free update out now" with the Steam, PS5 and Xbox logos.

The new dungeons and where to look

Cold Symmetry didn't publish names or locations. YouTube guide maker Esoterickk posted a route to every new entrance a day after launch, with these names:

• Troubadour's Reprise
• Primeval Dungeon
• Obscured Market (Ghost Beacon)
• Shrouded Mire (Ghost Beacon)
• The Corridors
• The Sideway
• Ankle's Bane
• Veiled Tower
• Well of Knowledge
• Buried Library
• Secret Alcove (Ghost Beacon)
• Concealed Lookout (Ghost Beacon)
• Icebound Chamber
• Not The Sheep Dungeon
• Neglected Ward

Here's the catch: in that video he says most, and maybe all, of them only open while Night Mode is on. Night Mode is the game's harder variant, and you unlock it with the Gloombound Flame near the start. If you never turned it on, that's step one. Players on the Steam forum are still mapping them, too. "I found 3 dungeons, but it seems one of them is located beneath the textures. Or perhaps I haven't met some requirement," one wrote (Steam discussion).

Screenshot: Mortal Shell II Rotten Autumn update trailer (Playstack YouTube channel)

One player in that thread singled out the first one. "Troubadour's reprise is one of the most fun dungeons in this :D lots of trying things out," they posted (Steam discussion).

"There is no sheep dungeon"

The Steam post signs off with a joke, insisting that "there is no sheep dungeon." One of the names on the list above is Not The Sheep Dungeon, so you can guess how seriously to take that. In the same forum thread, players posted screenshots of what they call a Diablo 2 Cow Level easter egg, done with sheep. The Sheep-specific Tarstone in the patch list fits the theme.

Hotfix 1: the October 30 patch notes

The first fix for the update, build 1.000.015, reached every platform on October 23 at about 800 MB on PC, and it came with no notes (MP1st). Cold Symmetry posted them a week later, on October 30, as "Rotten Autumn Hotfix 1" on Steam. The lines that touch Rotten Autumn: you can now re-enter the Sideways dungeon, encounter completion tracking in the Killer Ritual Dungeon is fixed, Night Mode no longer triggers inside the hub, the Wellspring Tarstone now reaches your inventory, and the new Shell Shades despawn when you're knocked out of your shell. Photo mode's scaling setting now applies, and snow no longer stays on after you leave it. The Overkill graphics setting can finally be selected, on PC only (Steam post; MortalShell2.lol transcription). The only buff in the list goes to the Waning Stone: its resolve cost drops 10% per level. Notes a week late are poor form, but if a new dungeon unloaded as you walked in, that's on the fix list, so update and try it again.

What it means for your save

The new Tarstones matter most if you're building around them. Our Mortal Shell II weapons tier list covers which weapons pair with which Tarstones, and the achievements guide lists the Stoned achievement for finding all of them. We couldn't confirm whether the new ones now count toward it, so check your list before you chase it.

Screenshot: Mortal Shell II Rotten Autumn update trailer (Playstack YouTube channel)

Some players already rate Night Mode highly. "night mode for difficulty increase is also genius," a 77-hour player wrote on October 22 (review). Now it has content of its own.

Our take

This is a good free update for people who already beat the game. A photo mode and a new soundtrack are nice, but the new dungeons are the real reason to come back, and they mostly live in Night Mode. New players won't notice much difference in the first hours. Our Mortal Shell II review still holds on the core game, and the Mortal Shell II complete guide covers Shells, Seals and the gate route. "There's more coming," the studio says, without a date.

How we checked this

We read the Rotten Autumn post in Steam's news feed for App ID 2584270 and checked the Steam store price and review summary (language=all, purchase_type=all) on October 22, 2026. Dungeon names and the Night Mode note come from Esoterickk's location video and its chapter list, published October 21. We watched the official update trailer on Playstack's YouTube channel for the timestamps and stills. Forum quotes come from the Steam discussion "I found a new dungeon :D". We have not played the update.

References

• Mortal Shell II: Rotten Autumn Update Brings New Content and Seasonal Treats: the official highlight list.
• Mortal Shell II on Steam: price and review summary.
• Mortal Shell II: Rotten Autumn Free Seasonal Update Out Now: Playstack's update trailer.
• All 15 New Dungeons Location Guide: Esoterickk's route and dungeon names.
• How To Unlock Night Mode: Esoterickk's Gloombound Flame video.
• I found a new dungeon :D: Steam discussion thread.
• Rotten Autumn Hotfix 1 - Live Now: the October 30 patch notes.
• Mortal Shell 2 Update 1.000.015 Released as Rotten Autumn Hotfix 1: MP1st on the October 23 build.
• Mortal Shell 2 Patch Notes: MortalShell2.lol's transcription of the hotfix notes.