Terrible frametimes, but otherwise the performance is OK.
I finished it, obtaining all six achievements.
Stuck on "Loading"
Tried it on both "Fantastic" and "Fastest" graphics settings. Didn't seem to make a difference.
Interestingly, in both cases the game had all 16 cores / 32 threads on my Threadripper in moderate use, so it was clearly doing something, but no idea what.
Starts but hangs on "Loading..." after choosing "Start".
Starts and shows menu. After click on "start" shows loading screen, background animation keeps moving but thats it. it loads forever.
Unity Engine based 'game'/demo which does not work on my 1000 games library Linux. Neither via Steam/Proton nor pure WINE. Via Steam/Proton it won't crash, accepts keyboard inputs, but won't render frames. Turning Unity Analytics off (option.ini file) makes no difference. Windowed/Fullscreen neither.
I tried "PROTON_USE_WINED3D=1" but it's no load.