The Rotten Autumn hotfix for Mortal Shell II lets players return to the Sideways dungeon after leaving it. It also changes Lazlo’s armor protection, fixes issues involving Proxima and makes the Overkill graphics setting selectable on PC.
The patch notes published on Steam on October 30, 2026 announce that the hotfix is live. The notes identify Overkill as a PC-only setting but do not detail which platforms receive the other changes.
Lazlo’s armor and Proxima’s abilities
Lazlo’s armor protection no longer persists after switching shells, and repeated uses no longer stack it. That changes how the protection can be used: players can no longer keep it through a shell change or accumulate it by activating the ability repeatedly.
For Proxima, the hotfix addresses separate problems involving her shell ability and survivability. Using a traversal gate immediately after the ability should no longer leave her melee weapon unequipped. The notes also announce a fix for an exploit that could make her invincible.
The Waning Stone receives a cost adjustment as well: its resolve cost is reduced by 10% per level. The notes do not give a further calculation formula, so the stated reduction is the available basis for assessing the change.
Sideways and dungeon transitions
Players can now revisit Sideways after leaving the dungeon. The change removes the previous restriction on returning, so leaving no longer ends access to that area.
Dungeon transitions also receive a smoother fade-in, background checkpoint saves and memory management improvements. Those changes accompany several announced crash fixes and stability improvements, including fixes involving Zmey and dungeons. The notes provide no performance measurements, and the fixes do not guarantee that every crash has been eliminated.
Wellspring Tarstone and Overkill
The hotfix addresses an issue that sometimes prevented the Wellspring Tarstone from being added to the inventory. The notes do not say whether a stone already missing from an affected player’s inventory will be restored.
On PC, Overkill can now be selected in the graphics settings. The notes identify the setting as PC-only; that restriction should not be read as a platform list for the rest of the hotfix.
For players affected by the Sideways restriction, the practical change is the ability to enter the dungeon again after leaving. Those using Lazlo should also account for the new limits on his armor protection when switching shells or repeating the ability.
See also the Mortal Shell II game page and our article on Mortal Shell II: Rotten Autumn adds 15 for free.
