


Technically, the way multiplayer works in this game requires no actual internet connection. You only need to be able to communicate with the other person (or yourself on another device) to share which version you are playing at the beginning.
You need two devices, each with their own paid copy of the game, to be able to play either in person or over distance. I had to buy a copy through my phone's app store.
Works as expected!

Works as expected, finished the entire game. Crashed a few times, but progress was saved so could just continue.
During the game, the game crashed three times (window just disappeared), possibly triggered by scrolling or other mouse input (or maybe it was just random). In all three cases, all progress was saved and I could just restart and continue playing. Finished the game as expected otherwise.
I selected "no" for multiplayer, but this game has no actual multiplayer mode (the game does not communicate other than via your own interactions based on information received from the other player).
I tried with Proton 9 instead of the preselected experimental because experimental did not seem like a good start (not realizing that that is what Steam apparently recommended to me), but I did not try with experimental, so maybe that also just works.

tried other proton versions, didn't even started the game; I used Proton 9.0-2 and it made the game almost playable...
PROTON_USE_WINED3D=1 %command%
serious bugs (after some time ~20-30 min some things just disappear, e.g. screwdriver or crystal...) and cannot go further with the script
I had to close game several times and replay it due to bugs
script broke (randomly) and I had to replay the game from the beginning
both players please use Windows
Runs out of the box Btw the multiplayer has no connection, so no problems with that

Played the game through fully. Stable the entire time.

Runs perfectly out of the box
Multiplayer runs completely offline, no network connection required. From a technical point this game is no different from a single-player title.
No issues playing with friend on who was running Windows
Completed the game with no hiccups. Excellent expierience.

Have to use Proton 7.0.3
Absolutely no problems
Works out of the box
Worked great out of the box on Steam Deck. Played all the way through co-op.