

PROTON_NO_D3D11=1 DXVK_FRAME_RATE=60 %command%
The game would start in fullscreen but alt-tabbing would make it windowed
On a multi-monitor setup the mouse doesn't stay locked on the game. This is fixed with PROTON_NO_D3D11=1. This shouldn't be neccessary if you only have one monitor
Physics get weird above 60fps so it is neccessary to lock it
Eagle Patch works as expected if you follow the instructions from their page and then add WINEDLLOVERRIDES="dinput8=n,b" as a launch option
I tried all the commands I could find. I had initial issues getting past the registration, but the menu never loads.
taskset -c 0-30 %command% WINEDLLOVERRIDES="dinput8=n,b" DXVK_FRAME_RATE=60 gamemoderun -windowed -d3d9ex -forcenovsync PROTON_NO_D3D11=1

Game just works fine. Start to a great franchise. The controls and general movement speed definitely show the game's age though.
Initial launch tries to get you to register, and to sign your soul away with a EULA (/s). Attempting to register launches the Wine browser / Internet Explorer clone. Registering is impossible in modern day, and there is no method to close the browser. Force quitting failed, unrecoverable without restarting Steam Deck.
No trouble on subsequent launches.
Initial successful launch can get you to the contoller settings to select a controller via touch screen.
Subsequent launches use the controller, but only after selecting save profile / choosing to go to the main menu via the touch screen. Minor annoyance.
Less than 3 total crashes in an entire playthrough, cause unclear. Safe to say "rare crashes."
EaglePatch can be used to improve graphics, or other retexturing mods. Not worth the effort in my opinion.

NO INTRO MOVIES: (game_root/Videos/) DemoIntro.bik -> DemoIntro.bik_bak UBI_LOGO.bik -> UBI_LOGO.bik_bak Ubisoft_Presents.bik -> Ubisoft_Presents.bik_bak Warning_Disclaimer.bik -> Warning_Disclaimer.bik_bak
GENERIC IMPROVEMENTS: (https://github.com/Sergeanur/EaglePatch) scripts to game_root, EaglePatch to scripts settings scripts/EaglePatchAC1.ini
Some reverb on some sounds relating to churches and computers
Alt-tab breaks fullscreen window, requires restart
Xboxone S bluetooth triggers don't work but not needed
Occasional pauses that become more common and longer throughout the game
Two crash to desktops for a full playthrough probably related to pauses

Ubisoft probleme generate Freezing/Lag More explain on this topic
Tips for Fix :
Open terminal and run this command ( if you have nano or by vim or other...)
sudo nano /etc/hosts
Copy and paste this at the end of the host file
127.0.0.1 gconnect.ubi.com
127.0.0.1 uts.ubi.com
Enjoy !
Freeze/Lag causing by ubisoft issue

On the first launch the game wants to be registered on Ubisoft servers. The in-game browser isn't supported by the Ubisoft website anymore, and it won't close - a full Steam Deck restart was needed. This never happened again despite the copy not being registered on the website.
On first launch, gamepad needs to be manually selected with mouse in the settings. On each subsequent launch, gamepad isn't recognized until a profile is selected. When using an external controller, it needs to be reordered.
Random crashes about once every 2 hours.
The game works fine. Be aware of the occassional crashes and setting up a controller. Beware the game not supporting steam cloud saves.

Uplay launcher is old and buggy. Requires on-screen keyboard, sometimes touch screen.
Had to use touchscreen to manually select controller in the game's menu. Otherwise, controller did not function.
This is one of those games that you'll have to spend so much time getting it to work for the first time that you'll not feel like playing anymore by the time it works. Between the Uplay Launcher being awful, controller not automatically working, etc, you'll quickly lose your motivation for playing this. Might be better/easier to emulate the PS3 or 360 version.

Honestly this games runs phenomenally even on my old hardware and running it with WINED3D instead of DXVK, though controller require tinkers
WINEDLLOVERRIDES="dinput8=n,b" PROTON_USE_WINED3D=1 %command%
I found when set to a lower resolution, instead of utilizing all areas of the screen, the game just became smaller
AC1 and AC2 has some issues with newer controllers, I had to use Sergeanur's EaglePatch for improved controller support and other nice stuff, this is also what WINEDLLOVERRIDES="dinput8=n,b"
is for
Honestly, if you play with Mouse and Keyboard it shouldn't be an issue (though I heard mouse and keyboard support is bad), playing with controller requires some tinkering either with the aforementioned EaglePatch or Steam Input configuration.
I still think the overall best way of playing the game is with EaglePatch and a controller though, as the EaglePatch also have some graphics settings improvements (if I understand correctly)
just works

-offline
Block fps on 40 when play on battery
You need to change manualy in game settings from keyboard and mouse to gamepad
It is good to change steamdeck controller settings and add enter button to some unsuable button to skip loading cinematic
I had some fps drops - not as much to disturb game If you have game frozen for few second try add -offline in launcher options (In my case helped)

Ubisoft Connect install script from Lutris
You have to manually enable the controller in the game's options menu. Was also an issue on my Windows machine, so not Proton related, but would be a hassle on the Steam Deck
Stutters every 60-120 seconds, explained below
Leap of Faith causes death when framerate was greater than 60, can be solved by locking the FPS or just enabling VSync
Played on Ubisoft Connect through Lutris, didn't own it on Steam
The game has a stutter every 60-120 seconds that lasts for around 1-2 seconds. This isn't a Proton issue, it's caused by the game trying to reach a server that doesn't exist anymore to upload your stats. The fix for this in Windows is to just block the IP from your "hosts" text file, but this didn't work for me. The only way other way to fix it is to unplug your ethernet cable/wifi adapter. This worked, but I didn't want to disable my internet for this game, so I just dealt with the stutter.
It's not a Proton-specific issue, but you can't fix it on Proton without disabling your internet.

Must go into the settings and enable the Xbox 360 controller instead of mouse and keyboard
Really good experience apart from the controller not being enabled out of the box and requiring touchscreen or touchpad input to select Profile in main menu.
gamemoderun %command%
Sometimes, especially during loading times, you can hear crackling audio. It's not a big issue, but it is noticeable. I don't know if this is a Linux/Proton issue, or if this is a just the game

taskset -c 0-30 %command%
Run's great overall. Assassin's Creed does not support 32 or more threads (i.e. CPUs with 16 or more cores). If you have a 16/+ core CPU, set these launch options taskset -c 0-30 %command
to let Assassin's Creed use only 31 threads (threads #0 up to thread #30).

WINEDLLOVERRIDES="dinput8=n,b" DXVK_FRAME_RATE=60 gamemoderun %command%
Xbox One S Controller not detected out of the box. Needed to install EaglePatch.
Game needs to be capped to 60 fps. Otherwise, you may experience physics bugs and the infamous "Leap of Faith bug". https://steamcommunity.com/app/15100/discussions/0/846965882681265985/
The game runs great on Linux. Just needs a few tweaks. These same tweaks would be needed on Windows for an optimal experience.

Worked perfectly fine out of the box
Lags every minute or so BUT this is related to Ubisoft! The game tries to contact servers which do not exist anymore so either you change config files (wwhich didnt work for me) or deactived the internet... So this has nothing to do with Proton!!
Profile needs to be created & selected with the trackpads (Holding Steam button)

gamemoderun %command%
Added DLL for up to date controller support
V-Sync can cause leaps of faith to kill you...
you need to change trackpad to a mouse for profile selection

change back grip or trackpad to mouse for profile creation, you must enable gamepad controls in the settings
Dialogs start to cut after first locaton. No matter what I tried, I unable to fix that

Vsync to lock 60FPs
need mouse to access the settings and change to controller
Crashed once
Stutter
D repack with Heroic, copy unpacked files and add game to launcher. works fine except occasional stutter.

Downloaded and started the game without any problems. It just works.

Installs and plays fine, just need to get controller configured
As others have reported, after starting the game, you have to use a mouse to set up a controller before it is recognised. Create a profile, go to Options->Cutomise Controls and click on controller. Then use the mouse to click the arrow unit (XBox 360 for windows) shows up. Click on Back to leave the options screen. At that point a few pushes on the controller d-pad, and the controller is recognized.
Using the Steam overlay, and Steam input options, the game starts fine, and after controller is set in options, it pays fine with my Stadia controller (which behaves like an XBox 360 clone).
Steam overlay is needed to exit the game (it has no "Exit game option"). To leave, just bring up the Steam overlay, and select the End Game option.

40fps
GE-Proton8-4 fixes this
To setup controller use touch screen/keyboard & mouse to create a save which will then give you input options

Starts up perfectly. Ran on big picture mode 3400x1440p ultrawide resolution no problem (with black bars).
DXVK_ASYNC=1 RADV_PERFTEST=aco mesa_glthread=true %command%
During the initial launch, you need to accept the Ubisoft computer specifications checker and product registration using a mouse or keyboard as the controller isn't functional at this stage. After creating a profile, you can switch the controller settings from keyboard/mouse to an Xbox 360 controller, and everything should work seamlessly. You will need to bind the "return" keyboard key to one of the controllers, and this is to select the profile you created, and after that you can use your controller as normal.
I wrote a script that would override the game's resolution in the configuration files to whatever was visible to XWAYLAND1. Worked great.
Turned a few settings down. Don't turn down LOD though, the models look terrifying.
This game doesn't select the correct gamepad when more than one is attached. When docked, set your gamepad to the lowest XInput slot, and then it works.
It's a Ubisoft game so it's a little unoptimized.
Works out of the box

Using an xbox controller. Triggers and right stick (look) were swapped. Luckily you can assign your own custom setup in the game settings, but for some reason a trigger was not allowed to be assigned for its default action.
Therefore, I had to use a bumper instead of a trigger, which works OK. So, the game is playable.
Except for the controller issue, the game works like a charm.
Changed back to Default Gamepad once I've set the profile and changed the controller settings to XBOX360. I also enabled 1 back grip button to Enter Key to skip the cinematic intro.
Settings the refresh rate to 40hz and framerate limit to 40fps.
Sometimes if you use the touchscreen to skip the cinematic intro, the controller sets back to keyboard and mouse. Best option is just set the back grip button to Enter Key.
The required uplay launcher is not required for the first game of the series.
DXVK_FRAME_RATE=60 PROTON_NO_D3D11=1 gamemoderun %command%
Sometimes an NPC repeats a word twice.
I play with DS4. To get it working I chose Controller (XBOX 360 For Windows) in Options Customize menu. By default all controls are mapped correctly. Also controller is available after you choose your game profile with KBM. Thanks to the reports below I found out "PROTON_NO_D3D10=1" is required otherwise you just get a black screen after the opening cinematic video. Limited frame rate to 60fps with "DXVK_FRAME_RATE=60", otherwise high frame rates cause you to die when performing a leap of faith, this can also be fixed by enabling vsync instead. This also seems to be an issue on windows.

Microstuttering - block ip request by adding two lines to hosts file
- 127.0.0.1 gconnect.ubi.com
- 127.0.0.1 uts.ubi.com
Aside from some controller weirdness I have had an incredible experience with this game on proton and it works better than on windows.
The default and community xbox one controller configs are not mapped properly, at least not in my opinion, x is y y is b etc. but this is easy to change so not a biggie.
On the first menu for selecting the profile/haracter sometimes you have to use the mouse and then the controller works fine for the rest of the game. It took me a while to realize this and spent a lot of time trying to mess with my controller cofigs but then i just clicked it with my mouse and in the next menu my controller was working.
Rubber banding
Alt-Tabbing causes fullscreen to become unavailable
Dualshock 4 controller would not work properly, KBM was fine
Launching for the first time requires to setup a profile, but the game doesnt detect any input. Set one of the buttons to "Enter", then type in the profile name afterwards I could use the touchscreen to get into the options and set the controls to "xbox 360 controller".
Its a minor annoyence to setup the controls, but after that the game runs perfectly. As noted below the game still has blackbars at 1280x800p. Intro scenes can be skipped with the touchscreen.
Runs just like native.
Worked out of the box once proton 7 was enabled. I also installed a fix for 21-9 displays which I obtained from WSGF. The exe swap worked.
Crashed once in around 5 hours so far