for those who have a black screen at startup:
download the demo from the dlsite
launch it
(possible 2 variants: 1) it work normaly from the first time, 2) it still black screen on first run, then close it and run second time, on second time usualy it will run but with vsync=on what lead to very slowappearing/disappearing of game logo (not unity))
go to the settings (3rd option from left if language not eng)
change the resolution for example to 1280x720 and [Windowed = ON] (it seems default 3k+x... in 3.1.4)
! make sure that vertical synchronization is disabled (it seems its ON by default in 3.1.4)
close settings
close demo
copy the newly created folder 'Records' from the demo version to the folder with 3.1.4
run 3.1.4 now it should work after unity logo
...it worked once and now black sceen again -_-
upd:
and now it runned with 1920x1080 FullScreen=On, vSysnc=On ... dont know what it whant...