Additional information: The game was made by Gust and seems to - according to the window name - even use the launcher of Atelier Shallie, which is rated Platinum on ProtonDB with slight tinkering.
Hello lone traveller from the future! In case anybody visits japan, buys the game and then encounters the same problems as I did, here is the solution to get everything running. Proton can't fix all of this, so you will need to tinker a bit.
The game needs the same workaround as all PC ports from Gust
d3d9.deferSurfaceCreation = True
add PROTON_USE_D9VK=1 to the launch options (click the cog in steam when you are on the games entry, choose "Manage", go to the "General" tab which should be already open and it's the last entry there)
I simply used this script to convert them:
#!/bin/bash for i in *.wmv; do ffmpeg -i "$i" -acodec pcm_s16le -vcodec copy "${i%.*}_new.wmv" done
Open /etc/locale.gen and remove the # in front of the ja_JP.UTF-8 entries
run "sudo locale-gen" in your terminal (on Steam Deck I was able to skip this step as my Deck was already set up to use Japanese. So on the Deck might not even need to tinker with that. Just set it up to use Japanese as you normally would)
Add this to the launch options in steam: LANG=ja_JP.UTF-8 HOST_LC_ALL=ja_JP.UTF-8
Your finished Steam launch options should look like this:
LANG=ja_JP.UTF-8 HOST_LC_ALL=ja_JP.UTF-8 PROTON_USE_D9VK=1 %command%
This solves all problems I have encountered so far. It even lets you open the settings menu in the launcher. If you don't want to use this menu or it's not opening for some other weird reason you can also edit the setting.ini directly. It's located under
/steamapps/compatdata/1477490/pfx/drive_c/users/steamuser/Documents/KoeiTecmo/ArnosurgeDX/
steamapps/compatdata/1477480/pfx/drive_c/users/steamuser/Documents/KoeiTecmo/CielnosurgeDX needs to be linked to /steamapps/compatdata/1477490/pfx/drive_c/users/steamuser/Documents/KoeiTecmo/
And the other way around:
/steamapps/compatdata/1477490/pfx/drive_c/users/steamuser/Documents/KoeiTecmo/ArnosurgeDX needs to be linked to /steamapps/compatdata/1477480/pfx/drive_c/users/steamuser/Documents/KoeiTecmo/
This worked for Desktop Linux and the SteamDeck for me. The performance on the latter is not as you might expect from a game with this level of graphics, but that's a problem of the game itself. It's not very well optimized and the port rather lackluster. I recommend turning down the shadows. Not much else you can do in terms of graphic settings.
Compatibility Report
System Information
GPU: RTX 2080
Video driver version: nvidia 550.78
Kernel version: 6.9.1-zen1-1-zen
Link to full system information report as Gist: https://gist.github.com/Keksus1/5f842f52c21ff2ad0638199c64429a87
Proton version: Experimental
I confirm:
steam-1477490_settingsmenu.log
steam-1477490_gamestart.log
Symptoms
Reproduction
Just launch the game with Proton without any tinkering.