

Work out of the box but you must set the Proton version to 8, otherwise it will crash at every cutscene.

Downgrade to Proton Version 8.0, works flawlessly.

Flikering on skill tree
The games has slowdowns when you do a Noble phantasm with some characters

Given >30 FPS, steamdeck performs much better than some other hand-console. However, frequent crash could be extremely discouraging.
I'm playing the asia version (simplified chinese). The fonts of text may probably be better randered/smoothed/anti-alising. But it is also probably the game's own problem, instead of steamdeck or proton.
我游玩的是简体中文版。我想中文字体如果能有更好的反锯齿,那么字会更清晰一些。但这更可能是游戏本身的问题,而非由于 steamdeck 或 proton 导致的问题。
Pre-rendered video in the game (such as skill/action demonstration) frequently causes the game to lock-up. Also refers to reports from Galm
and Solid Snack Drive
; I think I've encountered almost the same issue. For my case, lock-up means that only graphics freezes, including performance overlay (level 2). Still, pressing button on the frozen graphics, will give the sound effects as usual. So I believe that the game itself and sound are still working when locked-up, but only graphic frozen.
游戏中的演示视频 (譬如技能或动作演示) 经常导致游戏界面锁屏。我相信我遇到的问题与 用户 Galm
和 Solid Snack Drive
所碰到的问题非常相似。这里的锁屏是指,游戏画面、包括性能界面 (等级 2) 都被锁住不动;但同时按下按键可以听到游戏的声音是正常且符合运行逻辑的。因此,在锁屏发生时,我认为游戏和声音并没有停止工作,但仅仅是画面停止工作。

9-10w TDP, 30fps cap
Viewing any pre-rendered skill video has a decent chance of locking up the game. This occurs in the main skill menu and the controls menu shown before playing as servants other than Saber.
The video issues make this pretty annoying to play, as the skill menu is pretty important and accessed often. I also think this game performs pretty poorly for what it is, it often dips below 60 when unlocked and pretty much maxed out the power draw.

The game frequently crashes/locks-up because of pre-rendered video in the intro and also the skill menu.
installed video codecs
Game requires you to set specific settings and screen refresh options for the game logic to play at the correct speed
pre-rendered video in the game frequently causes the game to crash or lock-up. This can be replicated by launching the game in handheld mode then after closing and trying to re-open it while docked. The game will lock to a black screen at boot up. Also the worse and deal-breaker bug is the game frequently crashes when viewing the skill menu that has embedded pre-rendered video in the corner to show off the move you're going to unlock. It doesn't always lock up the game but I would say there's a 50-70% chance that your game will lock up when swapping between these different options in the skill menu
The game should not have a gold rating on protonDB nor should it be verified on deck

9w TDP, 30fps lock
Crackling after waking the deck from sleep mode using blutooth
Skill tree videos making the screen flash white
Do yourself a favor and do not aim for 60fps, you will need to unlock the TDP to reach that (and still, it won't be 100% stable).Whatever you do, do not pick the performance mode in the option at it will target 120fps and be unplayable. Either lower the refresh rate to 40-45 and keep the TDP high enough for that or lock it to 30fps and keep your TDP around 8-9 so you can enjoy more battery life at full speed. If you do, allow tearing in the steam overlay and enable in-game v-sync so you don't get extra input lag.

Flickering when in the skill upgrade menu
The game runs pretty well although as expected of a game like this, you can only play about 2 hours on a full charge even with settings on Low.
When messing around with the graphics settings the game felt like it was playing in slow motion, restarting the game seemed to fix the issue. Might be graphics settings related.

Set FPS to 30 for battery savings if needed.
I have had no issues running it out of the box. I have steam set to experimental proton by default.

gamemoderun %command%
"mangohud" launch option will cause game crash before the logo screen.

the skill tree causes a white flash when you hover over a skill with a video attached
Performance mode seems to cause the half-speed animation issue. Graphics mode was smooth as butter in comparison. not sure why.
no changes made to any settings

Runs extremely well on GE-Proton8-15, getting 60fps on medium-high settings. TO ADDRESS SLOWDOWN: CHANGE TO GRAPHICS MODE IN THE MAIN MENU
Easy fix for the slowdown issue, switch to Graphics mode in the title screen settings menu. If you use Performance mode, the game will try to run at 120fps and you'll experience the slowdown. With GE-Proton8-15 and Graphics mode, I'm comfortably getting 60fps on medium-high advanced settings with no slowdown. I was averaging a bit over 2 hours of battery life. You can probably tinker with lower TDP and graphics settings to get more efficient battery life.
The only bug I've encountered otherwise is a frequent screen flicker on the skill upgrade menu screens.

Renamed cutscene's folder
cutscenes won't play obviously
Update to the last report: (No patch has been released tho) trying to get the game working, I noticed that renaming the cutscene's folder of the game after starting it, makes the game to skip them all, instead of crashing the game like it was doing in my case. It's important to do it AFTER lauching, if you do it before, the game will not start at all.

CryoUtilites recommended settings
My dumbass set the TDP to 8, forgot to remove it and was one of the issues of slowdown. Removing the limit/setting it to 15 makes it more bearable but still noticeable
Medium settings, would advise just playing on PC to avoid annoyances. Apologies for any misinformation wrote the contribution late at night

Contrary to the reviews below, performance between all the mentioned protonGE versions still have the animation slowdown issue, causing it to be unplayable.
Feel free to try it out for yourself, but in my experience it's all the same, doesn't work at all

Keyboard/Mouse on steamdeck desktop mode wasn't working properly. Controllers on steamdeck's gaming mode works fine.
The game is reporting to be running at 60fps but character movement and animations seem to be happening at half speed.

Extremely smooth and scalable with the right Proton version. 55-60FPS average on medium settings with all effects enabled.
WARNING: DO NOT USE STEAM'S RECOMMENDED PROTON VERSION, OR GE-PROTON8-16.
Both have a VERY nasty crash bug that corrupts your save data, and it's caused by something vital to gameplay that only becomes available ~1.5-2 hours into the game.
I tried GE-Proton8-15 and GE-Proton8-6; both run it the same, so I'd assume that there are other GE-Proton8 versions that are stable. I tried a GE-Proton7 version and it failed to even launch under that.
Steam's recommended Proton version also renders the game incorrectly. Those GE-Proton8 versions don't have that issue, and render it correctly.
Please, please, PLEASE, do NOT use Steam's recommended Proton version or GE-Proton8-16. It'll make you think that the game doesn't work on the Deck at all--but it does, and extremely well, with the right Proton version. It's basically flawless with GE-Proton8-15, an absolute joy to play on the Deck. Don't be afraid to purchase it just because it's an Omega Force title; they actually did extensive testing to make sure it runs well on the Deck.

Runs without issue, no setup necessary.
Might take a minute to start up but all good otherwise. No issues with gameplay/framerate, audio, or cutscenes.

Game crash after logo prompted.
PROTON_ENABLE_NVAPI=1 VKD3D_CONFIG=dxr11 mangohud gamemoderun %command%
Tired Proton version: 6.3-8, 7.0-6, 8.0-3, experimental. Nothing helps.

Changed one cinematic file's name
Cinematics don't work, character images/tutorial or tips images are not being rendered
Keyboard does have a lot of input lag, sometimes doesnt even detect the key you're pressing, controller works perfectly tho
Some lag spikes
If you don't change the name/remove the file for the first cutscene when starting a new game it will crash. After Rider's first boss battle the game freezes.
Only able to launch it with Proton 7.0-6, other versions didn't start. To start a new game, you need to rename or delete "/FateSamuraiRemnant/ebc8c781/0a3b595e.bin". The rest of the cutscenes will be skipped, but the game will freeze after Rider's fight, so you can't progress further in the game. The cutscene problem is not related to Linux, as Koei Tecmo has already provided a "solution," which doesn't seem to fix anything. We'll have to wait for a patch to fix this issue; I'll update the report then. Apparently, it works fine on the Steam Deck.

Works well with nothing out of the ordinary but I'm just at the start, will update as I play further.

The game runs (near) perfectly
Whenever a pre-rendered video plays, the screen will flicker/flash briefly beforehand. Happens on both Proton Experimental and 8.0-3
In my two hours of playing, the bug with pre-rendered videos is the only one I've encountered.

Game animations slow down when there are lots of things to load, like the bug in Yakuza 3 on PC
The game itself runs fine enough, up until you enter a fight or crowded area. Then all the animations suddenly slowdown, causing barely playable gameplay. A shame as well, since this game would honestly run pretty well otherwise

All I had to do was swap to Proton 8.0-2 from the default and it was working. Appeared to crash upon trying to start the game otherwise.