Not sure if this is the right place to discuss this but what's the meaning of the Game compatibility - Unofficial tag?
The game is Steam Deck verified, it should work without issues.

Having the same problem on the Steam Deck. Have tried factory reset the steam deck and change the protonDB version, but seems to be a problem with the game

On Steam Deck, I believe the game was running well on Proton 7.0-4, but now, it crashes a short time after reaching the title screen on Proton 7.0-5 (and Proton 7.0-6rc, if I successfully activated it). A crash report window appears afterwards, but it disappears immediately.

For me downloading Proton GE fixed the issue and I have experienced no more crashes. So I guess it was a problem in the latest Proton versions.

Proton GE 42 fixed this for me

Proton ge is not officially supported by Valve

@kisak-valve: Here's the system info gist.

And steam-1850510.log

My memory may not be the most reliable thing here, but for what it's worth, I believe I had been playing Ver1.0.1 without issues prior to some non-game update on the Steam Deck (one where the client or system rebooted). I may be incorrectly assuming that included a Proton update from 7.0-4 to 7.0-5 and attributing the crash to a version number that didn't match my Ubuntu desktop at the time.

Now the two do match, and the game runs fine on my Ubuntu desktop with Proton 7.0-5. So, this crash may be specific to the Deck somehow.

@a-will Could you try renaming/moving the prefix on the deck where the game is currently failing with Proton 7.0-5? I am asking for you to do this instead of deleting the prefix, because if this does "fix" the game, it would be really helpful to have a copy of the broken prefix :). You can do this relatively easily by going into desktop mode and opening a terminal, and then running
"mv ~/.steam/steam/steamapps/compatdata/1850510 ~/.steam/steam/steamapps/compatdata/1850510.bak". Then reboot to get back to SteamOS deck mode, and try relaunching the game with Proton 7.0-5.

@alasky17 I'll note that this game currently resides on a microSD card. There was a prefix for this game both in the home folder's library and in the microSD card's library. I tried renaming them individually, then together, but the crash still occurred.

One interesting observation is that the prefix did not get recreated on the microSD card, and the last mtime for files there looks like it may be just before the crashing started happening. I can't say whether that's a red herring, but perhaps I ought to try moving the game to the home folder library and see if it makes a difference.

@a-will That is very interesting indeed. By default, the prefix for games stored on an SD card should be stored in the home folder's library on the deck (this is not true on desktop, only on the deck). It does hint that something is going wrong if you have a prefix there - and also give me something to try here too :D

@a-will I think that we figured out the mystery. The game had not been properly flagged as requiring h264. It likely worked on your desktop because you had already played some game there which unlocked h264. The game should be properly flagged now. It might require a restart to pick up the flag, but I'm hoping that now the game will suddenly work :)

@alasky17 Awesome sleuthing! I can confirm the crash no longer occurs. Thanks for the fix!

Apologies, I already got a refund for the game. I'll see tomorrow about picking it up again.

@atrauzzi Just as a note - we can't guarantee we can get the game to work for you even if you repurchase.

I know. Still, we gotta try.