


In Steam Deck Desktop Mode with fullscreen, moving the mouse cursor to top menubar may cause the mouse click not working. Using Alt-Tab to switch to other windows and then switch back to the game can fix this problem.
When starting the game in Steam Deck Desktop Mode with windowed screen, the screen may flicker or be low FPS. In Steam Deck Gaming Mode or fullscreen, screen is displayed normally.
OP can play with GE-Proton9-1. There is no need to install quartz.

protontricks 976390 quartz
no video out of box, install quartz to play it

install quartz
In Desktop Mode with fullscreen, moving the mouse cursor to top menubar may cause the mouse click not working. Using Alt-Tab to switch to other windows and then switch back to the game can fix this problem.
When starting the game in Desktop Mode with windowed screen, the screen may flicker or very low FPS. In Gaming Mode or fullscreen, screen is displayed normally.
Install quartz to play OP

install quartz
When starting the game in the desktop mode, the screen may flicker. In the gaming mode, screen is displayed normally.
Install quartz to play OP
runs out of the box
Reduced framerate to 30
Played flawlessly from start to finish.
Limit framerate to 40fps
Works out of the box
Installed H-patch available at https://denpasoft.com/product/9-nine-episode-1-18-dlc/. Just like on windows extract the adult.xp3 into the game directory.

A blackscreen may appear which I believe occurs when switching from the game's window. This is different from the initial menu blackscreen commonly experienced (which can be worked around by passing PROTON_USE_WINED3D=1 %command%) but if you experience this, simply maximize and minimize the window
By default the game does not limit the framerate so it will result in high CPU usage. To save battery, I recommend limiting the frame rate to at least 60 fps within the game's settings. It's an advanced option that's present beneath the game window's title bar, which will require you to exit full screen mode to see
Should be a smooth experience by switching to Proton Experimental (version 7) instead of vanilla Proton

PROTON_USE_WINED3D=1 %command%
For an untinkering experience, just use the latest Proton experimental provided by Steam to get around the black screen and to use Steam's runtime.

Black screen cant play
Used Proton 7.0rc6-GE-1. Installed quartz dll trough protontricks just like the other comments said but still got black screen. Tried out Proton 6.3 and didnt work

Black Screen, unplayable
Proton 6.3
When play the movie, can not resize the window.
Click the VersionInformation in Help Menu will make the game crash.
Thanks for pee pee's advises. The game can work very will.
- Use Proton-5.0-10
- Use protontricks to install the quartz.
protontricks 976390 quartz
If you not have protontricks, runpip install protontricks
to install. - Use winecfg to add quartz(native,buildin).
protontricks 976390 winecfg
In this step, my wine automatic help me to finished. So I did not do anything except confirm. If you find winegstreamer in your dlls list, please disable it. The most import things that you must make sure your wine environment enough CLEARLY. Except quartz, don't install other dlls. You can by removing "~/.local/share/Steam/steamapps/compatdata/976390/pfx/" folder and runing the game to generate a now environment. This method is also applicable to other 9-nines.

To get the movies working:
Install quartz with winetricks
In winecfg, add "quartz" as (native,builtin) and "winegstreamer" as (disabled)

Got the movies working in wine;
In winecfg, set os to windows xp, add library overrides for quartz as (native,builtin), for winegstreamer as disabled, install quartz with winetricks.On wine 5.13 or later (or manually install devenum on earlier versions).
Not tested on proton 5.13 or 5.0.
Incidentally, screen blacking out when touching the top does not happen on wine 5.10 (or earlier idk)
will black out when switching on certain versions of wine
Minor tearing during character movement
When the game launched on fullscreen, it will be fullscreen. But if the cursor went to the top of the screen where the toolbar is, the screen will turn black and need to switch to windowed. After in windowed mode, you can't go back to fullscreen, only windowed.
Last I played on Ubuntu, I can play using both the Proton 6.3-5 or Proton Experimental. However, if the game won't render on either of those versions, switch to 5.13-6. If you're using Flatpak to install Steam, most possibly the game just won't launch without any error. Use the native deb file from Steam instead!
just a black screen

5.11-GE-1-MF GloriousEggroll
When the mouse hits the top of the screen, the window gets black in both windowed and FS mode. For the image to be shown once again, you have to set it in the opposed mode (windowed if fs and vice versa). Once you got it set in windowed, the fullscreen won't be full anymore, being just a stripe at the top or a third of the screen at the right
Sometimes, when the controller is plugged, the game skips all of the text and it can't be stopped, if not by closing the game
if you're interested in japanese or chinese text, specifying the local by typing LC_ALL=ja_JP.UTF-8 or LC_ALL=zh_CN.UTF-8 in the launch options is all you need

To display Japanese text properly, set launch options: LC_ALL=ja_JP.UTF-8 %command%