

Works perfecly out of the box

The initial launch took several minutes, and multiple attempts - this might be game related because it happend on Win11 too
When the game finally launched, it was a blank screen and I had to click a few times to get started
Some graphical issues. Took several minutes and multiple attempts to launch the game but I think that might be an issue with the game itself because it's buggy on Win11 too.
The game launched to a black screen with the game's cursor. Had to click a few times to get to the title screen.

I was able to 100% the game without any issues outside of the graphical mishap during Urashima Woman
There was one instance during the first real "investigation" where it zooms into the boss and the vignette was stretched, happened every time as the game needs multiple playthroughs to 100%. Not game breaking but immersion breaking for sure.
You need to press through the intro sequence where it shows the companies involved, it hangs up like it has an issue loading the next logo. Also the credits have the same thing, but don't play. You can spam the A button on the Deck and it'll skip the credits and take you to saving a clear file.

Blackscreen and no audio on startup movies
Crashes at startup

Unable to get this working....
Tried with Proton 6.3-8, 5.9-GE-8-ST, 6.21-GE-2, 7.0rc6-GE-1 and proton experimental. The game launched into either a black screen or initial loading screen with mouse and then freezes once the steam community overlay pops up. Also tried forcing the game into windowed and running without proton but made no difference.
Unable to see any indication to faults from game log with the exception of when 5.9-GE-8-ST is used where the logs show some LD Preload errors.

Proton-5.9-GE-8-ST GloriousEggroll
You need https://github.com/GloriousEggroll/proton-ge-custom for it to work, played a little and it works good!