


Works Perfectly
+18 Patch region lock bypass: open "steam://install/967420" in a browser (desktop mode on steam deck)

PROTON_USE_WINED3D=1 %command%
Install via protontricks:
- wmp9
Refresh Rate:
- 60 hz
Thermal Power (TDP) Limit:
- 4 Watts
Windowed mode may crash the game
Tinkering fixes opening/ending movies, as well as effects that utilise movies, but will lengthen launch time in game mode.
Install wmp11 with protontricks
You can crank down the TDP and graphics power to near-minimum, if not all the way.
There's lots of animations (expression changes mid-line, etc) so 30-60 FPS is kinda recommended.
In game mode, it takes a significant amount of time (1.5-2 minutes) before you can see the game exe.
This issue isn't as prevalent if you launch it through desktop mode.
If you're facing graphical issues, adding PROTON_USE_WINED3D=1 %command%
to Properites > Launch Options, may fix it.
If you don't want to tinker at all, you can run it straight from install without any movie support (you won't face the long boot time issue in game mode)
Yes, but you lose out on the opening/ending movies, as well as some effects that are played as a movie (e.g. feathers scene)
You can crank down the TDP and graphics power to near-minimum, if not all the way.
There's lots of animations (expression changes mid-line, etc) so 30-60 FPS is kinda recommended.
Install wmp11 with protontricks.
The setup works but is limited to desktop mode -- it can't run in game mode.
If you can get behind skipping the opening/ending, as well as some effects (e.g. feathers -- they'll show up as a white box instead of playing properly), then you don't need any tinkering and can just play straight after installing without any modifications needed.
runs out of the box
works
use PROTON_USE_WINED3D=1 %command%
on Properties > Launch Options
use protontricks 888790 wmp11
(not 1277930, that's the appid for Riddle Joker), if any permission error appears just chmod 666
the offending files, and due to containerization and/or regression, I believe protontricks wmp11 does not work on 5.13 and higher, or with proton-ge (might be mistaken but I confirmed 5.0 works no issue).
The window does not play well with drag-and-drop, at least on GNOME 38. If you are going to move between monitor then I recommend using keyboard shortcut as it could otherwise cause the shell to get stuck trying to move the window for a long while (if it even unfreezes)
There doesn't seem to be any issue with R-18 patch, whether via DLC or normal installer. Audio becomes tiny if using more than x1.0 audio speed, but not sure if inherent in the game or only with Linux.

Everything works (including videos) if you install wmp11 and use the workaround mentioned
This is necessary to get the game to show instead of starting in a black screen. Alternatively, to get the game to show without the argument, launch it, click yes/no on the Direct3D error that shows up, and once it reboots, press ALT to open the top menu which should fix the black screen
Use protontricks 1277930 wmp11 to get videos to work
Minor issues with movies playing, otherwise perfect.
Movies don't play.
Small animation such as the "fragment of the heart" of Wakana in the Swartchze Katze was replaced by a white square.
Regular character animation transitions worked fine.
Changing window size, or resizing the window occasionally caused the window to remain black.
All essentials in a visual novel work perfectly.
Movies are skipped, and sometimes changing some display stuff in the menu bar (example, 4:3 mode) will cause the window to turn black, requiring the window to be resized to bring the game back.
The game itself runs very well, however everything else in the system runs not so well. This is a visual novel, so you might be alt+tabbing.

Movies get skipped, otherwise it works perfectly

Plays well for most part. Does not play movies. (Won't crash, the game just skips them.)