Works perfectly on ChromeOS, great alternative if you don't already have the Play Store version.

It just works
If not focused, music is stuttering ... not really an issue tho.

Works Flawlessly
Ran without any issues, brilliant game. Helpful to refer to unofficial wiki & discussion threads for strategies if you're new to deckbuilders

disabled back grip buttons so no accidental end turn
cloud saves only save overall stats/progress, not individual runs

gamemoderun %command%
Couldnt switch windows without it minimizing. It works on Windows tho
Works like native windows. Fullscreen minimizing when clicking outside is slightly annoying and only on Linux
No issues whatsoever.

Works great out of the box, couple edgy things to worry about if playing docked with mods
Added "touchscreen off" so that I could play the game docked with mods.
Only applies if you're using ModTheSpire. If playing docked need to set a joystick to act as trackpad with mouse click so that you can get through the mod menu.
Only a problem if switching between docked and handheld but - the in-game resolution setting doesn't respect the Steam Deck's resolution setting. This means that if you set the in-game setting high (I'd set mine to 4K for my TV, for example), the game is unplayable in handheld unless you switch the in-game resolution setting down to the Steam Deck's internal resolution before you undock. You can probably also do this in a config file in a pinch.

You can lower the TDP to below 5W for better battery life
Controller support is a little bit janky and can misinput

If you're on Kde Plasma. Switch to fullscreen
When "Borderless Fullscreen" is turned on, the panel is always on top and overlaps. Switching to "Fullscreen" fixes it and works well as intended
After that, It should work well

Works really well
No tinkering required to enjoy the game
does not sync between devices

Works right out of the box.

gamescope -f -W 1920 -H 1080 -- %command%
Wouldn't go in fullscreen (fixed using gamescope)
My problems are probably cosmic's fault, use gamescope to fix most problems
Works out of the box perfectly
Perfect out the box.

Works out of the box
There was a temporary hitch with a dependency not being available in the Steam Linux Runtime but now it is resolved. That of course means that this native build should remain playable for decades to come.

Flawless!
The game works perfectly without any additional steps.
TDP 3w - long life battery

I ran the game using Proton 9.0-3 and it worked out of the box.

I initially tried playing without proton and it generally worked, but prevented my mouse from displaying when the game was alt-tabbed. While using proton I had no issues.

mangohud %command%
Wenn ich das Spiel nativ starte, dann muss ich jedes Mal auf die Titleleiste mit Rechts klicken und den Vollbildmodus durch KDE erzwingen. Mit Proton/Wine läuft es besser. Übrigens auch mit Mod-Support.

replaced launcher with sh script to launch natively
Game always appers below taskbar with Borderless fullscreen on KDE Plasma 6 Wayland
Using windows gog version, launching natively on Linux using java -jar desktop-1.0.jar
works the same as on windows 10
Works natively out of the box.
Fullscreen borderless doesn't hide taskbar and equivalents. Regular fullscreen works as intended.

Works better with Proton
Native was working weird, starting in a small 720p window (and changing resolution did not work) on a wrong monitor. Proton works fine.

Use proton experimental
I was not able to move game window to my main display when borderless fullscreen is enabled. Also, with fullscreen I was not able to interact with other windows at all.
I would recommend enabling Proton in Steam if you experience issues with borderless-/fullscreen.

Fullscreen 2560*1600 required, steam input required
Panel in Cinnamon is always ontop with borderless fullscreen
Without proton, steam input is required, with proton, steam input must be disabled

Worked prefectly staight out of the box.

Apenas jogar e se divertir

works OOTB.