

I just changed compatibility to Proton 10.0-1 (beta)

After following the advice of other people here on ProtonDB and on Reddit, I tried using Proton-Sarek10-8 to try and fix the issue of being stuck in the loading screen and not getting into the game, and it works perfectly. I have tried the base Proton Steam provides as well as GE-Proton and both do not work. I guess it may have something to do with older NVIDIA cards, but I'm not sure.
Baseline Proton is missing VP9 required for the gacha part and some other parts of the game

UMU_ID=0 %command%
In-game web browser has issues rendering font.
Was able to get past the Black Screen of Death via the UMU_ID=0 %command% launch option and the Proton-GE fork. Game has worked smoothly beyond the menu. Have not tested purchasing in game. In-game browser has rendering issues, but this does not affect normal gameplay.

The only thing that didn't work on non-GE Proton was the little videos playing on the recruitment page. They were black instead, but IMO it's such a minor thing it's barely worth mentioning.

Only the videos in the Recruit screen do not play on the default Proton install. Using GE-Proton fixes that minor issue.

crackling happened when computer is under heavy load, like during initial start up, or when tabbed out. otherwise everything is normal
windowing is janky
Game crashes at launch when using default compatibility settings and Proton Experimental. Using Proton 9.0-4 made it possible to launch the game but only up until start screen as it get stuck in loading screen.
The game was able to launch and proceed to the main menu with custom Proton (Proton-Sarek10-8). Gameplay is smooth and no noticable issues so far.
Ran on Debian with default KDE on Wayland

UMU_ID=0 PROTON_USE_WINED3D=1 %command%
Giant magenta blocks or backgrounds, very annoying and looks ugly, but doesn't impact playability. I've heard this happens on Windows too.

Previews don't play on the Recruit page, and Mimori (Swimsuit)'s EX Skill has small black square artifacts.
Windowed mode is so flickery it's basically unusable. Fullscreen works well, but forcefully grabs focus sometimes, even when on a different workspace.

If you spam input while in-between loading, it will show black screen. Audio still works, and you can interact with it, but the black screen blocks the visual.
If you're stuck like me previously, try ABSOLUTELY every proton variant, at least in ProtonPlus. I was disregarding Proton-Sarek at the beginning, since it was advertised for older PC. A bit of a Hail Mary later, it works! So try everything first before giving up.

You won't get past the starting screen, so use Proton Hotfix instead, Mouse/Keyboard input won't accept on Proton Experimental [bleeding-edge]

You won't get past starting screen if you don't use Proton Hotfix, tested on Proton Experimental [bleeding-edge]

Game runs smoothly without any tinkering needed.

UMU_ID=0 %command%
I had a crash 1 time while loading into the main menu, but so far they haven't been, I'll leave it like this
Game didn't react at clicks by mouse, maybe it's game 'cause this problem is present in the mobile version

처음 실행 시 데스크톱 모드에서 실행하지 않는 것을 권장합니다. 화면 크기를 잘못 잡습니다.

UMU_ID=0 %command%
Tried Proton 9.0.4, hotfix, experimental and GE-10.8, but all stuck at loading screen. Proton-Sarek10-8 finally fixed this issue. All aspect of gameplay are working normally.
Works out of the box

The game runs like a breeze on Linux! It even managed to generate Gacha video and title screen pictures flawlessly, better than Windows!
This has been tested on Artix Linux Cinnamon with OpenRC. The performance beats Windows 11 by a huge landslide(Windows couldn't render the gacha videos for example)! Everything and I mean everything works fine! Note that it only works on the package manager version of Steam. It won't work with Snaps or Flatpak. With Artix, the distro I used, you need to install and add Arch repos. You also need Proton experimental for the game to function!

Black Screen after Intro Sequence and Menu
Able to play the introduction/tutorial, but anything past that, including reseting the game to the menu, results in a black screen. Changing Proton versions does not change the outcome.

Text wasn't inputted sometimes.
Worked perfectly fine for me on Hyprland.

need to keep vsync enabled to prevent the game from running "bad" (quotations marks, kinda weird), maybe only happens if you have a high refresh rate monitor... not sure, but it works great with this
keep vsync enabled (for this game in particular, as i explained before) and it should run perfectly

Tested with Proton Experimental, Hotfix, 10.0, 9.0, and Proton GE 10-8.
Occurs rarely
May cause a black screen and you need to resart the game to fix. Also windowing does not work sometimes.
Some videos do not load properly in some proton versions. Use the default (9.0) and Proton GE 10-8 to fix.

Even thought this game now playable on my PC, but for me this is the most R*tarded experiences ever happened on my Linux gaming session....
UMU_ID=0 %command%
It's so hard to me to run this game for the first time...either you stuck at "unpacking files" on loading menu or "Resetting game data" after. At least, for me need a day to figured out how to makes this game work, and guide on community does not helpful at all.
If you're ever encounter this problem all you need to do is having this game installed at your main drives (same folder like steam) otherwise it won't work and stuck between these 2 problem. It might has something todo with their anti-cheat system...

Can't get to home menu
Couldn't get into the game. With whatever the default Proton was, I was stuck loading for Nexon Game Security or whatever it's called.
I was able to run game on latest ProtonGE (10-8) after creating a new steamcompat pfx, but I got stuck when I got to the end of the tutorial (since I clicked guest account instead of immediately logging in to Nexon ID).
Couldn't get to Home Menu at all, even after changing Nexon ID and changing which game id Steam should use on Windows.

Using the official Proton (I tested with Proton 9.0-4) makes the game throw error messages during almost every interaction. Switching to Proton GE resolves the issue.
The game works perfectly: gameplay is smooth, and there don’t appear to be any errors with dialogue (both text and audio). Recollection Lobbies display correctly, and interactions work just fine.
Social features also seem to be working as expected, and the “Notice” window loads without a problem. I logged into the forum through it and read a few posts just to test.

It works fine, but the activity information when logging into the game cannot be displayed (WebUI)
Only minor issue is the event information banner (likely a WebUI or CEF window) not displaying. This does not impact gameplay in any way.
Game runs flawlessly out of the box with Proton, no tweaks or overrides required. Rendering is perfect: 3D combat scenes, menus, and Live2D characters all display correctly.
Using MangoHud shows Vulkan as the active rendering API. No DXVK involved.
Surprisingly, the game runs very smoothly on Intel UHD 630 integrated graphics — playable at 40–50 FPS.

Never tested on Windows.
Some gacha preview animations do not display
Anticheat works on Linux. When it pops up a white anticheat screen (with a Nexon logo in the top bar), just close it.
Game works well on Hyprland. Fullscreen is fine.
For regionlocked users, connect to a VPN first before launching this game for the first time (and keep it on during first login). After that you may login without VPN.

Game runs smooth with no tinkering. Recommended

In a club chat non-latin characters (e.g. cyrillic) turns into ?
Works pretty well, stable 60 fps

As long as ur fine with installing a custom proton version with Proton plus, it should fine
Had to install a custom version of proton (Proton-Sarek 10-8) as Proton 10.0-1, 9.0-4, Experimental and Hotfix didnt work. Its probably because my gpu is very old

I tried it with Proton experimental, GE-Proton 10-8 and the version of Proton that Steam recommends by default and had no problems with either, but I would recommend Proton GE 10-8 for a better experience.

prime-run %command%
Works

Tested with various proton versions, including experimental and proton GE.
May cause a black screen and you need to resart the game to fix
Some videos may not load properly using Proton Experimental. Not an issue with the default version (9.0) and Proton GE