FIELD GUIDEMORTAL SHELL II
Mortal Shell II Rotten Autumn Update
Sources checked: October 22, 2026. Announcement research; no independent in-game testing.
Official Rotten Autumn trailer artwork, published with the October 20 update announcement. Promotional art, not a screenshot of a dungeon route or an unlock step.
Official Rotten Autumn announcement and trailer© Playstack and Cold Symmetry
What Can I Do After Updating?
| Your goal | Confirmed addition | Useful next read |
|---|---|---|
| Explore more | 15 new dungeons and a lost-Shell ghost offering cryptic notes. | Dungeon changes in the patch notes |
| Revisit a build | 10 new Tarstones; a sheep-specific Tarstone is also listed. | Check a build against recent changes |
| Change your look | New Shades for every Shell, a Harbinger pumpkin helmet and an Impervious Lute skin. | Shell names and ability notes |
| Capture or change the mood | Photo Mode, Nightmode lighting presets, Overkill graphics settings, new lute tracks and an alternative soundtrack by Sakis Tolis. | Separate difficulty from presentation settings |
Choose your next Rotten Autumn activity
- New areas
Explore
15 new dungeons; the announcement does not map their entrances.
- Build options
Revisit equipment
10 new Tarstones, with a sheep-specific stone also listed.
- Cosmetics
Change appearance
New Shell Shades, pumpkin headgear and an Impervious Lute skin.
- Presentation
Capture the world
Photo Mode, Nightmode lighting, Overkill graphics and new music.
Where Are the New Dungeons and Shell Shades?
The announcement confirms the additions, but does not name all 15 dungeons, map their entrances or describe each Shade’s unlock condition. It also does not say that every cosmetic is handed out automatically. A guide for the first Mortal Shell’s similarly named update does not establish a route in this sequel.
If you are following a location tip, compare the exact Shell, area label and game version with your save before travelling there. Our older village pages are exploration notes; they are not a location list for these 15 additions.
The world image used on the official Rotten Autumn announcement. The source does not identify this scene as one of the 15 new dungeons or map an entrance.
Official October 20 Steam announcement header© Playstack and Cold Symmetry
Are There 10 or 11 New Tarstones?
The official list gives 10 new Tarstones and separately mentions a sheep-specific Tarstone. It does not clarify whether that stone is included in the ten. We therefore do not turn the two lines into a total of eleven. Individual names, effects and acquisition routes need their own evidence before they can support a build recommendation.
Photo Mode, Overkill and Nightmode Lighting
These are announced presentation features. The post does not document Photo Mode’s shortcut or menu path, nor does it provide a hardware benchmark for Overkill. Nightmode lighting presets do not establish a change to Adaptive Difficulty. If you are comparing settings on PC, record the existing setup and change one option at a time; use the PC troubleshooting guide for crashes or persistent stutter.
The gallery scene below shows Mortal Shell II’s world for visual context. It predates this update and is not a Photo Mode interface or an example of a new lighting preset.
Official in-game screenshot: an armored warrior in a cavern. It is not a settings, achievement or save-recovery screenshot.
Official Mortal Shell II gallery© Playstack and Cold Symmetry
Returning for Ova or a Summon Build?
Read the Ova and NG+ notes and Shell ability changes alongside this update. The October 13 hotfix contains specific progression and summon corrections; Rotten Autumn’s general promise of bug fixes does not prove that every outstanding issue has been resolved.
Sources: Team Mortal Shell’s October 20 announcement · Official announcement history. All gameplay additions are attributed to the developer; the comparison advice is editorial.