Official game facts
OFFICIAL PATCH RECORD
What Week 1 officially fixed
The developer lists improvements to Steam Deck detection and controller support in the Week 1 platform section. The same update also addresses controller firing, glyphs, rumble, frame generation, ray tracing, shader compilation and broader performance issues.
- Improved Steam Deck detection
- Improved Steam Deck controller support
- Fixed firing on some controllers
- Corrected controller glyph and rumble behavior
OFFICIAL PATCH RECORD
What is not claimed
A patch mentioning Steam Deck is not the same as Valve's Steam Deck Verified or Playable rating. The source also does not publish a fixed Deck frame-rate target, battery estimate or recommended graphics preset, so this page does not manufacture one.
OFFICIAL PATCH RECORD
Safe first check
- Install the current update
- Restart the device after the update finishes
- Test with the default controller layer before changing Steam Input
- Allow shader work to complete before judging stutter
- Record the game version when reporting a remaining issue
Recommended path
CONNECTED INTELLIGENCE PATH
Follow the evidence network
How we verify this guide
Our editors prioritize official storefronts and first-party patch notes. Community discoveries do not become confirmed facts without independent verification.
Sources
Facts checked September 7, 2026. Review percentages and prices are time-sensitive snapshots, never editorial scores.
Frequently asked questions
Is Mortal Shell II Steam Deck Verified?+
This source set does not establish a Valve Verified rating. It only confirms developer fixes for Deck detection and controller support.
Did Week 1 improve Deck support?+
Yes. The official patch explicitly names Steam Deck detection and controller-support improvements.