


-window
I've played Castle Crashers on Mac, Windows, and Ubuntu, in that order. Historically, Castle Crashers has been finnicky with fullscreen and alt-tabbing on all OSes. I recommend borderless if you really prefer a fullscreen experience

Try Proton 8.0-5.

If you don't mind a messed up audio, the game runs perfectly fine
The games audio would randomly turn into an unpleasant mess of white noise and 8-bit like sounds for a couple of seconds and then return to normal again, which it does several times per minute. The game has a great soundtrack, which to me is an integral part of the gameplay to set the mood, so this issue makes it kinda unbearable for me to play it. I have not experienced this issue a couple of years ago on the same OS with very similar hardware, so a recent update of the game might have messed something up?
Works perfectly out of the box

-window
Steam overlay sometimes doesn't show up

Dock your Deck and dominate those enemies. It works great on Deck; it deserves its verified status.
PROTON_USE_WINED3D=1 %command%

Amazing experience!
Nothing extraordinary to report.
just works on anything but arch. see previous report if arch user

PROTON_USE_WINED3D=1 %command%
works online with friends well
use PROTON_USE_WINED3D=1 %command% to get the game working

-window
Playable, but need to add -window into setting

It lags slightly when a lot of particles are on screen, But that might just be high GPU usage.

-window
It will not open or start unless the “-window” is passed as a launch option.

borked
Tried 7, 9 and experimental. All of them are borked. Refuses to even start.

I was trying for almost a week now to get this working. After the previous comment I gave the final shot and it was playing 100%
PROTON_USE_WINED3D=1 %command%
I first ran with Big Picture so far

PROTON_USE_WINED3D=1 %command%
If the game didn't appear on the screen and you use Wayland, add PROTON_USE_WINED3D=1 %command%
in launch options to solve the problem.
No response to any button on the Steam Deck, to get the game to start.

Game made Steam OS crash multiple times while playing with friends. Controllers are switching characters randomly. Bad experience.
Some controllers were randomly switching characters. Meaning for example some of my friends were the green and then suddenly they were the purple guy. Very confusing
At the first real boss the game not only crashed but made my steam deck restart its operating system. Multiple times and on the same part of the game. This while playing with friends. It made me embarrassed of my console in front of everyone.
What I said earlier about controllers switching between characters super randomly. Annoying.
If there is the badge that I don't own the game is because I asked for the refund. Terrible experience on the Deck.
Works great out of the box

-window
If the game does not start or open, pass '-window' as launch parameter(X11)
Tried different Proton and launch optiony but the game just don't starts. It keeps crashing just after the steam logo appears.
Game breaks in fullscreen when Alt Tabbing / changing focus. Changing to windowed mode in settings then adding the Hyprland windowrule windowrulev2 = fullscreen, class:^(steam_app_204360)$
works fine.
the game runs perfectly out of the box
gamemoderun mangohud %command%

Click and play experience
Had a kinda high input lag but the same happend with my friends on windows, so it's not a linux issue
I managed to beat the game in coop with no issues

Audio crackling and game lag issues, was fixed by using Proton-7.1-GE-2
Well done Valve and Proton Team
Works perfectly as expected, no issues.

Slight lag with couch play

TDP at 7w and GPU at 700.
Not a single issue with the online play; worked like a dream.
Would recommend
I can play with my friend just fine
Fun and it works
Nothing shows on the screen, Steam takes a while to realise it isn't actually running.
Tried multiple GE versions, no Proton, Proton Experimental, different Proton versions, all to no avail at all. Disabling the overlay did nothing, too.
Significant FPS drops when any character is engaged in combat
FPS drops when any character on screen is fighting
Awesome game - perfect for the Deck.